9.3 — Lvalue references – Learn C++

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Wed Mar 16 2022 19:35:13 GMT+0000 (Coordinated Universal Time)

Saved by @pham24n #c++

int main()
{
    int& invalidRef;   // error: references must be initialized

    int x { 5 };
    int& ref { x }; // okay: reference to int is bound to int variable

    return 0;
}

https://www.learncpp.com/cpp-tutorial/lvalue-references/

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8.13 — Function templates – Learn C++ 9.3 — Lvalue references – Learn C++ 9.3 — Lvalue references – Learn C++ 9.3 — Lvalue references – Learn C++ 9.5 — Pass by lvalue reference – Learn C++

**8.11 (Game: nine heads and tails)

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;




void decToBinary(int n)
{
    // array to store binary number 
    int binaryNum[3][3];
    
    //converting to binary 
    for (int i = 0; i < 3; i++) 
    {
        for (int j = 0; j < 3; j++)
        {
            binaryNum[i][j] = n % 2;
            n = n / 2;

        }
     }       

    // printing binary> array in reverse order 
    for (int i = 3-1; i >= 0; i--){
        for (int j = 3 - 1; j >= 0; j--)
        {
            if (binaryNum[i][j] == 0)
                cout << "H" << " ";
            else
                cout << "T" << " ";
        }
        cout << endl;
    }
    
 }

int main()
{
    int n;
    cout << "Enter a decimal number between 1 and 512 ";
    cin >> n;

    decToBinary(n);
    return 0;
}

#include<iostream>
using namespace std;
bool issafe(int** arr,int x,int y,int n){
    for(int row=0;row<=x;row++){
        if(arr[x][y]==1){
            return false;
        }
    }
    int row=x;
    int col=y;
    while(row>=0 && col>=0){
        if(arr[row][col]==1){
            return false;
        }
        row--;
        col--;
    }
     row=x;
     col=y;
    while(row>=0 && col<n){
        if(arr[row][col]==1){
            return false;
        }
        row--;
        col++;
    }
    return true ;
}
bool nqueen(int** arr,int x,int n){
    if(x>=n){
        return true;
    }
    for(int col=0;col<=n;col++){
        if(issafe(arr,x,col,n)){
            arr[x][col]==1;
            if(nqueen(arr,x+1,n)){
                return true;
            }
            arr[x][col]=0;  //backtracking
            
        }
    }
    return false;
}
int main(){
    int n;
    cin>>n;
    int** arr=new int*[n];
    for(int i=0;i<n;i++){
        arr[i]=new int[n];
        for(int j=0;j<n;j++){
            arr[i][j]=0;

        }
    }
    if(nqueen(arr,0,n)){
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                cout<<arr[i][j]<<"";
            }cout<<endl;
        }
    }


    return 0;
}

#c++ #algorithms #interviewquestions #arrays

Kadane’s Algorithm

int maxSubArraySum(int a[], int size) 
{ 
int max_so_far = 0, max_ending_here = 0; 
for (int i = 0; i < size; i++) 
{ 
	max_ending_here = max_ending_here + a[i]; 
	if (max_ending_here < 0) 
		max_ending_here = 0; 

	/* Do not compare for all elements. Compare only 
		when max_ending_here > 0 */
	else if (max_so_far < max_ending_here) 
		max_so_far = max_ending_here; 
} 
return max_so_far; 
}

Write a program that displays the first 100 emirps

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;


bool primeNumber(int n);
bool Emirp(int n);
int reversal(int n);
int recursive(int a, int b);

int main()
{
	
	int count = 0;
	int number = 13;
	while (count <= 100)
	{
		if (Emirp(number))
		{
			count++;
			if (count % 10 == 0)
				cout << setw(7) << number << endl;
			else
				cout << setw(7) << number;
		}
		number++;
	}
		

}
bool primeNumber(int n) {
	
		for (int i = 2; i <= n / 2; i++) {
			
			if (n % i == 0) {

				return false;
			}
		}
		return true;
}

bool Emirp(int n) {
	

	return primeNumber(n) && primeNumber(reversal(n));
	
}

int reversal(int n) {
	
		if (n < 10) {
			
				return n;
			
		}
		return recursive(n % 10, n / 10);
	
}

int recursive(int a, int b) {

	if (b < 1) {

		return a;

	}
	return recursive(a * 10 + b % 10, b / 10);
	
}

Difference Between ios::ate and ios::app

https://stackoverflow.com/questions/10359702/c-filehandling-difference-between-iosapp-and-iosate#:~:text=ios%3A%3Aapp%20%22set%20the,file%20when%20you%20open%20it.&text=The%20ios%3A%3Aate%20option,to%20the%20end%20of%20file.

#include<iostream>
using namespace std;

int sum(int arr[], int a);

int main() {
    int arr[1000], n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> arr[i];
        cout << sum(arr, n);
    }
}
int sum(int arr[], int a) {
    int i;
    sum = 0;
    for (i=0; i<n; ++i) {
        sum += arr[i];
    }
    return sum;
}#include<iostream>
using namespace std;

int sum(int arr[], int a);

int main() {
    int arr[1000], n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> arr[i];
        cout << sum(arr, n);
    }
}
int sum(int arr[], int a) {
    int i;
    sum = 0;
    for (i=0; i<n; ++i) {
        sum += arr[i];
    }
    return sum;
}

(Display the Sundays in a month) Write a program that prompts the user to enter the month and first day of the month, and displays all the Sundays in that month. For example, if the user entered the month 7 for July, and the first day 4 for Wednesday, your program should display the following output: The first day of this month is Wednesday! ... Next Sunday of this month is on 26

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;

int main()
{
	cout << "enter the month ";
	int month;
	cin >> month;
	cout << "Enter The First Day Of The Month ";
	int firstDay;
	cin >> firstDay;
	int nextSunday = 1;
	
		switch (firstDay)
		{
			
		case 1: nextSunday += 7;
			cout << "The first day of this month is sunday "<<endl;
			while (nextSunday < 30)
			{
					cout << "Next Sunday of this month is on " << nextSunday << endl;
									nextSunday += 7 ;
			}
			break;

		case 2: nextSunday += 6;
			cout << "The first day of this month is monday " << endl;
			while (nextSunday < 30)
			{
				cout << "Next Sunday of this month is on " << nextSunday << endl;
				nextSunday += 7;
			}
			break;
		case 3: nextSunday += 5;
			cout << "The first day of this month is tuesday " << endl;
			while (nextSunday < 30)
			{
				cout << "Next Sunday of this month is on " << nextSunday << endl;
				nextSunday += 7;
			}
			break;
		case 4: nextSunday += 4;
			cout << "The first day of this month is wednesday " << endl;
			while (nextSunday < 30)
			{
				cout << "Next Sunday of this month is on " << nextSunday << endl;
				nextSunday += 7;
			}
			break;
		case 5: nextSunday += 3;
			cout << "The first dayof this month is thursday " << endl;
			while (nextSunday < 30)
			{
				cout << "Next Sunday of this month is on " << nextSunday << endl;
				nextSunday += 7;
			}
			break;
		case 6: nextSunday += 2;
			cout << "The first day of this month is friday " << endl;
			while (nextSunday < 30)
			{
				cout << "Next Sunday of this month is on " << nextSunday << endl;
				nextSunday += 7;
			}
			break;
		case 7: nextSunday += 1;
			cout << "The first day of this month is saturday " << endl;
			while (nextSunday < 30)
			{
				cout << "Next Sunday of this month is on " << nextSunday << endl;
				nextSunday += 7;
			}
			break;

		}
		
}

(Display calendars) Write a program that prompts the user to enter the year and first day of the year and displays the calendar table for the year on the console. For example, if the user entered the year 2013 and 2 for Tuesday, January 1, 2013, your program should display the calendar for each month in the year, as follows:

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;

int main()
{
	cout << "enter the year ";
	int year;
	cin >> year;
	
	cout << "Enter The First Day Of The year ";
	int FirstDay;
	cin >> FirstDay;
	int count = 1;
	int days = 1;
	for (int month = 1; month <= 12; month++)
	{
		cout << "             ";
		switch (month)
		{
		case 1: cout << "January " << year<<endl;
			break;
		case 2: cout << "February " << year << endl;
			break;
		case 3: cout << "March  " << year << endl;
			break;
		case 4: cout << "April  " << year << endl;
			break;
		case 5: cout << "May " << year << endl;
			break;
		case 6: cout << "June  " << year << endl;
			break;
		case 7: cout << "July  " << year << endl;
			break;
		case 8: cout << "August " << year << endl;
			break;
		case 9: cout << "September " << year << endl;
			break;
		case 10: cout << "October " << year << endl;
			break;
		case 11: cout << "November " << year << endl;
			break;
		case 12: cout << "December " << year << endl;
			break;
		}
		cout << " --------------------------------------------------------- "<<endl;
		cout << "  Sun Mon Tue Wed Thu Fri Sat"<<endl;
		for (int i = 0; i < FirstDay; i++)
		{
			cout << "    ";
		}
		for (int i = 1; i < 31; i++)
		{
			if (i < 10) {
				cout<<"   " <<i;
			}
			else {
				cout<<"  " << i;
			}
			if ((i + FirstDay) % 7 == 0) {
				cout << endl;
			}
		}
		cout << endl;

		FirstDay = (FirstDay + 31) % 7;
		
	}
	
	
}

(Pattern recognition: consecutive four equal numbers) Write the following function that tests whether a two-dimensional array has four consecutive numbers of the same value, either horizontally, vertically, or diagonally.

#include <iostream>
#include<cmath>
#include<ctime>
#include<string>
#include <iomanip>
#include <fstream>

using namespace std;


bool  isConsecutiveFour(int values[][7]) {

    // checking rows
    for (int i = 0; i < 6; i++) {
       
        int current = values[i][0];
        int consecutiveCount = 0; // values[i][0] starts count

        for (int j = 0; j < 7; j++) {
            
            if (values[i][j] == current) {
                consecutiveCount++;
                if (consecutiveCount == 4) return true;
            }
            else {
                current = values[i][j];
                consecutiveCount = 1;
            }
        }
    }
    // check columns
    for (int j = 0; j < 7; j++) {
        
        int consecutiveCount = 0; // values[0][j] starts count
        int current = values[0][j];

        for (int i = 0; i < 6; i++) {

            if (values[i][j] == current) {
                consecutiveCount++;
                if (consecutiveCount == 4) return true;
            }
            else {
                current = values[i][j];
                consecutiveCount = 1;
            }

        }
    }

    // check topLeft side: going upright
    for (int i = 6 - 1; i > 0; i--) {
        int y = i;
        int x = 0;
        int consecutive = 0;
        int current = values[y][x];

        while (y >= 0) {
           
            if (values[y][x] == current) {
                consecutive++;
                if (consecutive == 4) return true;
            }
            else {
                consecutive = 1;
                current = values[y][x];
            }
            x++;
            y--;
        }
    }

    // check bottom right side: going upright
    for (int j = 0; j < 7; j++) {
        int y = 6 - 1;
        int x = j;
        int consecutive = 0;
        int current = values[y][x];

        while (x < 6 && y >= 0) {
            
            if (values[y][x] == current) {
                consecutive++;
                if (consecutive == 4) return true;
            }
            else {
                consecutive = 1;
                current = values[y][x];
            }
            x++;
            y--;
        }

    }

    // check bottom left side going up-left
    for (int j = 7 - 1; j > 0; j--) {

        int x = j;
        int y = 6 - 1;
        int current = values[y][x];
        int consecutiveCount = 0;

        while (x >= 0 && y >= 0) {

            if (values[y][x] == current) {
                consecutiveCount++;
                if (consecutiveCount == 4) return true;
            }
            else {
                consecutiveCount = 1;
                current = values[y][x];
            }

            x--;
            y--;
        }
    }
    // check bottom right side going up-left
    for (int row = 1; row < 6; row++) {
        int x = 7 - 1;
        int y = row;
        int consecutive = 0;
        int current = values[y][x];

        while (y >= 0) {
            
            if (values[y][x] == current) {
                consecutive++;
                if (consecutive == 4) return true;
            }
            else {
                consecutive = 1;
                current = values[y][x];
            }
            x--;
            y--;
        }

    }
    return false;
}






// Driver code
int main()
{
    int m[6][7];
    for (int i = 0; i < 6; i++)
        for (int j = 0; j < 7; j++)
            cin >> m[i][j];
    if (isConsecutiveFour(m) == true)
        cout << "true";
    else 
        cout << "false";
  
}

yourHand_GlobalIntrerfacev1.0_firmware

///LIBRARIES & SPECIFIC PARAMETERS
#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>
#include <U8g2lib.h>

Adafruit_PWMServoDriver servo = Adafruit_PWMServoDriver(0x40);  //ServoMotor Driver Controller I2C Address
U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); //OLED Constructor

//- - - - VARIABLES & METHODS - - - -//

#define jky 13              //Joystick button pin
#define emgPin A0           //EMG signal pin
#define emgThreshold 500    //EMG signal detection threshold   

/*----OLED Display & Driver----*/
void u8g2_prepare(void) {
  u8g2.setFontMode(1);              //Enable Transparent Font
  u8g2.setFont(u8g2_font_6x13_tf);  //Set font Width: 6px / Height: 13px
  u8g2.setFontRefHeightExtendedText();    
  u8g2.setFontPosTop();             //Origin Position of Text
  u8g2.setFontDirection(0);         //Font direction 0º
}
//Custom Drawn Symbols
static const unsigned char back[] U8X8_PROGMEM  = {
  0x04, 0x06, 0x7F, 0x86, 0x84, 0x60, };

/*---- Servo Driver Variables ----*/
#define Freq (uint8_t) 50     //Servo working frequency

#define posMin 102
#define posMax 512

//Finger Number Assignation for Servo Control
#define thumb (uint8_t) 0
#define index (uint8_t) 1
#define middle (uint8_t) 2 
#define ring (uint8_t) 3
#define pinky (uint8_t) 4
#define wrist (uint8_t) 5

//Method to map servo position from pulses to degrees
void setServo(uint8_t n_servo, uint8_t angulo){
  int duty;
  duty=map(angulo, 0, 180, posMin, posMax);
  servo.setPWM(n_servo, 0, duty);
}

//Method for EMG signal detection and actuation
void emg(void (*pointer)()){
  if((analogRead(A0))>emgThreshold){
    pointer();    
  }
  else{
    openHand();
  }
}

/*---- Hand Movements Methods ----*/
void closeHand(void){
    setServo(thumb,170);
    setServo(index,170);
    setServo(middle,175);
    setServo(ring,151);
    setServo(pinky,161);
    setServo(wrist,180);
}
void openHand(void){
    setServo(thumb,13);
    setServo(index,10 );
    setServo(middle,13);
    setServo(ring,13);
    setServo(pinky,13);
    setServo(wrist,180);
}
void rock_servo(void){
    setServo(thumb,170);
    setServo(index,13);
    setServo(middle,175);
    setServo(ring,151);
    setServo(pinky,13);
    setServo(wrist,180);
}
void ronaldinho_servo(){
    setServo(thumb,13);
    setServo(index,156);
    setServo(middle,145);
    setServo(ring,151);
    setServo(pinky,13);
    while(analogRead(A0)>emgThreshold){
      setServo(wrist,150);
      delay(400);
      setServo(wrist,180);
      delay(500);
    }
}
void point_servo(void){
    setServo(thumb,170);
    setServo(index,13);
    setServo(middle,145);
    setServo(ring,151);
    setServo(pinky,161);
    setServo(wrist,180);
}
void thumbsUp_servo(void){
    setServo(thumb,13);
    setServo(index,156);
    setServo(middle,145);
    setServo(ring,151);
    setServo(pinky,161);
    setServo(wrist,180);
}

/*---- Joystick Button----*/
#define jkyX A1
#define jkyY A2

uint8_t swbtn_state=0;    // Memory Storage Byte
bool btn_val=0;           // Current state of the button
bool btn_oldVal=1;        // Previous state of the button  

//Joystick Button Method
void btn_Jky(uint8_t x){
  btn_val=digitalRead(jky);   // read pin button
  if (btn_val == LOW && btn_oldVal == HIGH){
      swbtn_state=x;    
      delay(10);   
  }
  btn_oldVal=btn_val;
}

/*- *- *- *- - MENU SYSTEM - -* -* -* -*/
uint8_t M1 = 0; //Memory variable to determine menu state
uint8_t F1 = 0; //Memory variable to determine menu state
uint8_t C1 = 0; //Memory variable to determine menu state

//Mode_options
#define openClose (uint8_t) 1
#define figures (uint8_t)   2
#define custom  (uint8_t)   3

//Figures_options
#define rock (uint8_t)       1
#define ronaldinho (uint8_t) 2
#define point (uint8_t)      3
#define thumbUp (uint8_t)    4
#define goBackF1 (uint8_t)   5

//Custom_options
#define thumb (uint8_t)    1
#define index (uint8_t)    2
#define middle (uint8_t)   3
#define ring (uint8_t)     4
#define pinky (uint8_t)    5
#define wrist (uint8_t)    6
#define goBackC1 (uint8_t) 7

/*---- 1.MODES Menu Methods / All Menu Systems ----*/
/*-- Read Joystic M1 Method --*/
void jkyM1(void){
  if (analogRead(jkyX)<=341 && analogRead(jkyY)>=1010){
    M1 = openClose;
  }
  else if (analogRead(jkyX)>=342 && analogRead(jkyX)<=682 && analogRead(jkyY)>=990){
    M1 = figures;
  }
  else if (analogRead(jkyX)>=683 && analogRead(jkyX)<=1023 && analogRead(jkyY)>=980){
    M1 = custom;
  } 
}

/*---- Modes Screen Methods ----*/
void M1_openClose(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(32, 45, "OPEN/CLOSE");
  
  u8g2.drawBox(8,0,31,31);   //Selected box
  u8g2.drawStr(21,9, "1");   //Selected string
  
  u8g2.drawFrame(47,0,31,31);
  u8g2.drawStr(60,9, "2");
  
  u8g2.drawFrame(86,0,31,31);
  u8g2.drawStr(99,9, "3");
  
  u8g2.sendBuffer();
}
void M1_openClose_in(){
  emg(closeHand); 
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(32, 16, "Squeeze to");
  u8g2.drawStr(32, 32, "CLOSE HAND");
  
  u8g2.sendBuffer();
}
void M1_figures(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(42, 45, "FIGURES");
  
  u8g2.drawFrame(8,0,31,31);   
  u8g2.drawStr(21,9, "1");
  
  u8g2.drawBox(47,0,31,31);   //Selected box
  u8g2.drawStr(60,9, "2");    //Selected string
  
  u8g2.drawFrame(86,0,31,31);
  u8g2.drawStr(99,9, "3");
  
  u8g2.sendBuffer();
}
void M1_custom(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(19, 45, "CUSTOM MOVEMENT");
  
  u8g2.drawFrame(8,0,31,31);   
  u8g2.drawStr(21,9, "1");
  
  u8g2.drawFrame(47,0,31,31);   
  u8g2.drawStr(60,9, "2");
  
  u8g2.drawBox(86,0,31,31);   //Selected box
  u8g2.drawStr(99,9, "3");    //Selected string
  
  u8g2.sendBuffer();
}

//MAIN MENU SYSTEM(MODES) METHOD
void modes_M1(){  
  switch (M1){
    case openClose:
      if(swbtn_state==1){
        M1_openClose_in();
        btn_Jky(0);
      }
      else{
        jkyM1();
        openHand();
        M1_openClose();
        btn_Jky(1);
      }
      break;

    case figures:
      if(swbtn_state==2 || swbtn_state==3){
        figures_F1();
      }
      else{
        jkyM1();
        openHand();
        M1_figures();
        btn_Jky(2);
      }
      break;

    case custom:
      if(swbtn_state==4 || swbtn_state==5){
        custom_C1();
      }
      else{
        jkyM1();
        openHand();
        M1_custom();
        btn_Jky(4);
      }
      break;
  }
}

/*---- 2.FIGURES Menu Methods ----*/
/*-- Read Joystic F1 Method --*/
void jkyF1(void){
  if (analogRead(jkyX)<=150 && analogRead(jkyY)>=1022){
    F1 = rock;
  }
  else if (analogRead(jkyX)>=151 && analogRead(jkyX)<=540 && analogRead(jkyY)>=1022){
    F1 = ronaldinho;
  }
  else if (analogRead(jkyX)>=541 && analogRead(jkyX)<=767 && analogRead(jkyY)>=1022){
    F1 = point;
  }
  else if (analogRead(jkyX)>=768 && analogRead(jkyX)<=1023 && analogRead(jkyY)>=1022){
    F1 = thumbUp;
  }
  else if (analogRead(jkyX)>=400 && analogRead(jkyX)<=1023 && analogRead(jkyY)<=400){
    F1 = goBackF1;
  } 
}

/*---- Figures Screen Methods ----*/
void F1_rock(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(32, 32, "ROCK'N ROLL");
  
  u8g2.drawBox(11,0,17,17);   //Selected box
  u8g2.drawStr(17,2, "1");    //Selected string 
  
  u8g2.drawFrame(39,0,17,17);
  u8g2.drawStr(45,2, "2");
  
  u8g2.drawFrame(67,0,17,17);
  u8g2.drawStr(73,2, "3");
  
  u8g2.drawFrame(95,0,17,17);
  u8g2.drawStr(101,2, "4");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();

}
void F1_rock_in(void){
  emg(rock_servo);
  btn_Jky(2);
  u8g2.clearBuffer();
  
  u8g2.drawStr(32, 16, "Squeeze to");
  u8g2.drawStr(32, 32, "ROCK'N ROLL");
  
  u8g2.sendBuffer();
}
void F1_ronaldinho(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(34, 32, "RONALDINHO");
  
  u8g2.drawFrame(11,0,17,17);
  u8g2.drawStr(17,2, "1");
  
  u8g2.drawBox(39,0,17,17);   //Selected box
  u8g2.drawStr(45,2, "2");    //Selected string
  
  u8g2.drawFrame(67,0,17,17);
  u8g2.drawStr(73,2, "3");
  
  u8g2.drawFrame(95,0,17,17);
  u8g2.drawStr(101,2, "4");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}
void F1_ronaldinho_in(void){
  emg(ronaldinho_servo);
  btn_Jky(2);
  u8g2.clearBuffer();
  
  u8g2.drawStr(32, 32, "RONALDINHO!");
  
  u8g2.sendBuffer();
}
void F1_point(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(49, 32, "POINT");
  
  u8g2.drawFrame(11,0,17,17);
  u8g2.drawStr(17,2, "1");
  
  u8g2.drawFrame(39,0,17,17);     
  u8g2.drawStr(45,2, "2");
  
  u8g2.drawBox(67,0,17,17);   //Selected box
  u8g2.drawStr(73,2, "3");    //Selected string
  
  u8g2.drawFrame(95,0,17,17);
  u8g2.drawStr(101,2, "4");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}
void F1_point_in(void){
  emg(point_servo);
  btn_Jky(2);
  u8g2.clearBuffer();
  
  u8g2.drawStr(32, 16, "Squeeze to");
  u8g2.drawStr(49, 32, "POINT");
  
  u8g2.sendBuffer();
}
void F1_thumbUp(){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(39, 32, "THUMBS UP");
  
  u8g2.drawFrame(11,0,17,17);
  u8g2.drawStr(17,2, "1");
  
  u8g2.drawFrame(39,0,17,17);     
  u8g2.drawStr(45,2, "2");
  
  u8g2.drawFrame(67,0,17,17);     
  u8g2.drawStr(73,2, "3");
  
  u8g2.drawBox(95,0,17,17);     //Selected box
  u8g2.drawStr(101,2, "4");     //Selected string
  
  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}
void F1_thumbUp_in(void){
  emg(thumbsUp_servo);
  btn_Jky(2);
  u8g2.clearBuffer();
  
  u8g2.drawStr(20, 16, "Squeeze to give");
  u8g2.drawStr(32, 30, "a THUMBS UP");
  
  u8g2.sendBuffer();
}
void F1_goBack(void){
  btn_Jky(0);  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(42, 32, "GO BACK");
  
  u8g2.drawFrame(11,0,17,17);
  u8g2.drawStr(17,2, "1");
  
  u8g2.drawFrame(39,0,17,17);     
  u8g2.drawStr(45,2, "2");
  
  u8g2.drawFrame(67,0,17,17);     
  u8g2.drawStr(73,2, "3");
  
  u8g2.drawFrame(95,0,17,17);
  u8g2.drawStr(101,2, "4");    

  u8g2.drawBox(115,51,12,10);   //Selected box
  
  u8g2.setDrawColor(0);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}

//MAIN FIGURES METHOD
void figures_F1(){
  switch (F1){
    case rock:
      if(swbtn_state==3){ //s'ha de canviar!!
        F1_rock_in();
      }
      else{
        btn_Jky(3);
        jkyF1();
        F1_rock();  //print on display F1_rock
      }
      break;
    
    case ronaldinho: 
      if(swbtn_state==3){ //s'ha de canviar!!
        F1_ronaldinho_in(); 
      }
      else{
        btn_Jky(3);
        jkyF1();
        F1_ronaldinho(); //print on display F1_ronaldinho
      }
      break;
    
    case point:
      if(swbtn_state==3){ //s'ha de canviar!!
        F1_point_in(); 
      }
      else{
        btn_Jky(3);
        jkyF1();
        F1_point(); //print on display F1_ronaldinho
      }
      break;

     case thumbUp:
      if(swbtn_state==3){ //s'ha de canviar!!
        F1_thumbUp_in(); 
      }
      else{
        btn_Jky(3);
        jkyF1();
        F1_thumbUp(); //print on display F1_ronaldinho
      }
      break;

     case goBackF1:
        jkyF1();
        F1_goBack(); //print on display F1_ronaldinho
      break;
  }
}

/*---- 3.CUSTOM Menu Methods ----*/
/*-- Read Joystic C1 Method --*/
void jkyC1(void){
  if (analogRead(jkyX)<=170 && analogRead(jkyY)>=1023){
    C1 = thumb;
  }
  else if (analogRead(jkyX)>=171 && analogRead(jkyX)<=341 && analogRead(jkyY)>=1023){
    C1 = index;
  }
  else if (analogRead(jkyX)>=342 && analogRead(jkyX)<=511 && analogRead(jkyY)>=1023){
    C1 = middle;
  }
  else if (analogRead(jkyX)>=512 && analogRead(jkyX)<=682 && analogRead(jkyY)>=1023){
    C1 = ring;
  }
  else if (analogRead(jkyX)>=683 && analogRead(jkyX)<=853 && analogRead(jkyY)>=1023){
    C1 = pinky;
  }
  else if (analogRead(jkyX)>=854 && analogRead(jkyX)<=1023 && analogRead(jkyY)>=1023){
    C1 = wrist;
  }
  else if (analogRead(jkyX)>=512 && analogRead(jkyX)<=1023 && analogRead(jkyY)<=450){
    C1 = goBackC1;
  }
}
/*-- Movement State for Individual Fingers Method --*/
uint8_t movement=0;
void jky_servo_movement(void){
    if(analogRead(jkyY)>=600){
        movement=1;
    }
    else if(analogRead(jkyY)<=400){
        movement=2;
    }
    else if(analogRead(jkyY)>=401 && analogRead(jkyY)<=599){
        movement=0;
    }
}

/*---- Custom Screen Methods ----*/
void C1_thumb(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(49, 32, "THUMB");
  
  u8g2.drawBox(2,0,17,17);   //Selected box
  u8g2.drawStr(8,2, "1");    //Selected string
  
  u8g2.drawFrame(23,0,17,17);
  u8g2.drawStr(29,2, "2");
  
  u8g2.drawFrame(44,0,17,17);
  u8g2.drawStr(50,2, "3");
  
  u8g2.drawFrame(65,0,17,17);
  u8g2.drawStr(71,2, "4");

  u8g2.drawFrame(86,0,17,17);
  u8g2.drawStr(92,2, "5");

  u8g2.drawFrame(107,0,17,17);
  u8g2.drawStr(113,2, "6");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}

#define thumbMin 13
#define thumbMax 170
uint8_t thumb_angle=13;
uint8_t thumb_percentage=0;

void C1_thumb_in(void){
    jky_servo_movement();
    btn_Jky(4);
    if(movement==1 && thumb_angle<thumbMax){
        thumb_angle++;
    }
    else if(movement==2 && thumb_angle>thumbMin){
        thumb_angle--;
    }
    setServo(0,thumb_angle);
    thumb_percentage=map(thumb_angle, thumbMin, thumbMax, 0, 100);
    String percentage = String(thumb_percentage);
  
    u8g2.clearBuffer();
    u8g2.setDrawColor(2);
  
    u8g2.drawStr(16, 0, "Adjust Position");

    u8g2.drawStr(12,24, "Thumb:");
    u8g2.drawStr(64,24, percentage.c_str());   //map variable for %
    u8g2.drawStr(82,24, "%");
    
    u8g2.drawFrame(12,40,102,17);
    u8g2.drawBox(13,41,thumb_percentage,15);   //x is percentage of map
    
    u8g2.sendBuffer();
  
}
void C1_index(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(49, 32, "INDEX");
  
  u8g2.drawFrame(2,0,17,17);   
  u8g2.drawStr(8,2, "1");
  
  u8g2.drawBox(23,0,17,17);   //Selected box
  u8g2.drawStr(29,2, "2");     //Selected string
  
  u8g2.drawFrame(44,0,17,17);
  u8g2.drawStr(50,2, "3");
  
  u8g2.drawFrame(65,0,17,17);
  u8g2.drawStr(71,2, "4");

  u8g2.drawFrame(86,0,17,17);
  u8g2.drawStr(92,2, "5");

  u8g2.drawFrame(107,0,17,17);
  u8g2.drawStr(113,2, "6");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);

  u8g2.sendBuffer();
}

#define indexMin 10
#define indexMax 170
uint8_t index_angle=10;
uint8_t index_percentage=0;

void C1_index_in(){
  jky_servo_movement();
  btn_Jky(4);
  if(movement==1 && index_angle<indexMax){
      index_angle++;
  }
  else if(movement==2 && index_angle>indexMin){
      index_angle--;
  }
  setServo(1,index_angle);
  index_percentage=map(index_angle, indexMin, indexMax, 0, 100);
  String percentage = String(index_percentage);
  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(16, 0, "Adjust Position");

  u8g2.drawStr(12,24, "Index:");
  u8g2.drawStr(64,24, percentage.c_str());   //map variable for %
  u8g2.drawStr(82,24, "%");
    
  u8g2.drawFrame(12,40,102,17);
  u8g2.drawBox(13,41,index_percentage,15);   //x is percentage of map
    
  u8g2.sendBuffer();
}
void C1_middle(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(47, 32, "MIDDLE");
  
  u8g2.drawFrame(2,0,17,17);   
  u8g2.drawStr(8,2, "1");
  
  u8g2.drawFrame(23,0,17,17);   
  u8g2.drawStr(29,2, "2");
  
  u8g2.drawBox(44,0,17,17);   //Selected box
  u8g2.drawStr(50,2, "3");    //Selected string
  
  u8g2.drawFrame(65,0,17,17);
  u8g2.drawStr(71,2, "4");

  u8g2.drawFrame(86,0,17,17);
  u8g2.drawStr(92,2, "5");

  u8g2.drawFrame(107,0,17,17);
  u8g2.drawStr(113,2, "6");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}

#define middleMin 13
#define middleMax 175
uint8_t middle_angle=13;
uint8_t middle_percentage=0;

void C1_middle_in(void){
  jky_servo_movement();
  btn_Jky(4);
  if(movement==1 && middle_angle<middleMax){
      middle_angle++;
  }
  else if(movement==2 && middle_angle>middleMin){
      middle_angle--;
  }
  setServo(2,middle_angle);
  middle_percentage=map(middle_angle, middleMin, middleMax, 0, 100);
  String percentage = String(middle_percentage);
  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(16, 0, "Adjust Position");

  u8g2.drawStr(12,24, "Middle:");
  u8g2.drawStr(64,24, percentage.c_str());   //map variable for %
  u8g2.drawStr(82,24, "%");
    
  u8g2.drawFrame(12,40,102,17);
  u8g2.drawBox(13,41,middle_percentage,15);   //x is percentage of map
    
  u8g2.sendBuffer();
}
void C1_ring(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(52, 32, "RING");
  
  u8g2.drawFrame(2,0,17,17);   
  u8g2.drawStr(8,2, "1");
  
  u8g2.drawFrame(23,0,17,17);   
  u8g2.drawStr(29,2, "2");
  
  u8g2.drawFrame(44,0,17,17);
  u8g2.drawStr(50,2, "3");
  
  u8g2.drawBox(65,0,17,17);   //Selected box
  u8g2.drawStr(71,2, "4");    //Selected string
  
  u8g2.drawFrame(86,0,17,17);
  u8g2.drawStr(92,2, "5");

  u8g2.drawFrame(107,0,17,17);
  u8g2.drawStr(113,2, "6");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}

#define ringMin 13
#define ringMax 151
uint8_t ring_angle=13;
uint8_t ring_percentage=0;

void C1_ring_in(void){
  jky_servo_movement();
  btn_Jky(4);
  if(movement==1 && ring_angle<ringMax){
      ring_angle++;
  }
  else if(movement==2 && ring_angle>ringMin){
      ring_angle--;
  }
  setServo(3,ring_angle);
  ring_percentage=map(ring_angle, ringMin, ringMax, 0, 100);
  String percentage = String(ring_percentage);
  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(16, 0, "Adjust Position");

  u8g2.drawStr(12,24, "Ring:");
  u8g2.drawStr(64,24, percentage.c_str());   //map variable for %
  u8g2.drawStr(82,24, "%");
    
  u8g2.drawFrame(12,40,102,17);
  u8g2.drawBox(13,41,ring_percentage,15);   //x is percentage of map
    
  u8g2.sendBuffer();
}
void C1_pinky(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(49, 32, "PINKY");
  
  u8g2.drawFrame(2,0,17,17);   
  u8g2.drawStr(8,2, "1");
  
  u8g2.drawFrame(23,0,17,17);   
  u8g2.drawStr(29,2, "2");
  
  u8g2.drawFrame(44,0,17,17);   
  u8g2.drawStr(50,2, "3");
  
  u8g2.drawFrame(65,0,17,17);
  u8g2.drawStr(71,2, "4");

  u8g2.drawBox(86,0,17,17);   //Selected box
  u8g2.drawStr(92,2, "5");    //Selected string

  u8g2.drawFrame(107,0,17,17);
  u8g2.drawStr(113,2, "6");

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}

#define pinkyMin 13
#define pinkyMax 161
uint8_t pinky_angle=13;
uint8_t pinky_percentage=0;

void C1_pinky_in(void){
  jky_servo_movement();
  btn_Jky(4);
  if(movement==1 && pinky_angle<pinkyMax){
      pinky_angle++;
  }
  else if(movement==2 && pinky_angle>pinkyMin){
      pinky_angle--;
  }
  setServo(4,pinky_angle);
  pinky_percentage=map(pinky_angle, pinkyMin, pinkyMax, 0, 100);
  String percentage = String(pinky_percentage);
  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(16, 0, "Adjust Position");

  u8g2.drawStr(12,24, "Pinky:");
  u8g2.drawStr(64,24, percentage.c_str());   //map variable for %
  u8g2.drawStr(82,24, "%");
    
  u8g2.drawFrame(12,40,102,17);
  u8g2.drawBox(13,41,middle_percentage,15);   //x is percentage of map
    
  u8g2.sendBuffer();
}
void C1_wrist(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(49, 32, "WRIST");
  
  u8g2.drawFrame(2,0,17,17);   
  u8g2.drawStr(8,2, "1");
  
  u8g2.drawFrame(23,0,17,17);   
  u8g2.drawStr(29,2, "2");
  
  u8g2.drawFrame(44,0,17,17);   
  u8g2.drawStr(50,2, "3");
  
  u8g2.drawFrame(65,0,17,17);
  u8g2.drawStr(71,2, "4");

  u8g2.drawFrame(86,0,17,17);
  u8g2.drawStr(92,2, "5");

  u8g2.drawBox(107,0,17,17);    //Selected box
  u8g2.drawStr(113,2, "6");     //Selected string

  u8g2.drawFrame(115,51,12,10);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  
  u8g2.sendBuffer();
}

#define wristMin 180
#define wristMax 150
uint8_t wrist_angle=180;
uint8_t wrist_percentage=0;

void C1_wrist_in(void){
  jky_servo_movement();
  btn_Jky(4);
  if(movement==1 && wrist_angle>wristMax){
      wrist_angle--;
  }
  else if(movement==2 && wrist_angle<wristMin){
      wrist_angle++;
  }
  setServo(5,wrist_angle);
  wrist_percentage=map(wrist_angle, wristMin, wristMax, 0, 100);
  String percentage = String(wrist_percentage);
  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(16, 0, "Adjust Position");

  u8g2.drawStr(12,24, "Wrist:");
  u8g2.drawStr(64,24, percentage.c_str());   //map variable for %
  u8g2.drawStr(82,24, "%");
    
  u8g2.drawFrame(12,40,102,17);
  u8g2.drawBox(13,41,wrist_percentage,15);   //x is percentage of map
    
  u8g2.sendBuffer();
}
void C1_goBack(void){  
  u8g2.clearBuffer();
  u8g2.setDrawColor(2);
  
  u8g2.drawStr(43, 32, "GO BACK");
  
  u8g2.drawFrame(2,0,17,17);   
  u8g2.drawStr(8,2, "1");
  
  u8g2.drawFrame(23,0,17,17);   
  u8g2.drawStr(29,2, "2");
  
  u8g2.drawFrame(44,0,17,17);   
  u8g2.drawStr(50,2, "3");
  
  u8g2.drawFrame(65,0,17,17);
  u8g2.drawStr(71,2, "4");

  u8g2.drawFrame(86,0,17,17);
  u8g2.drawStr(92,2, "5");

  u8g2.drawFrame(107,0,17,17);
  u8g2.drawStr(113,2, "6");
  
  u8g2.drawBox(115,51,12,10);   //Selected box
  
  u8g2.setDrawColor(0);
  u8g2.drawXBMP(117, 53, 8, 6, back);
  u8g2.sendBuffer();
}

//MAIN CUSTOM METHOD
void custom_C1(void){
  switch(C1){
    case thumb:
      if(swbtn_state==5){
        jky_servo_movement();
        C1_thumb_in();
      }
      else{
        btn_Jky(5);
        jkyC1();
        C1_thumb();  //print on display F1_rock
      }
      break;
    
    case index:
      if(swbtn_state==5){ //s'ha de canviar!!
        C1_index_in();
      }
      else{
        btn_Jky(5);
        jkyC1();
        C1_index();  //print on display F1_rock
      }
      break;
    
    case middle:
      if(swbtn_state==5){ //s'ha de canviar!!
        C1_middle_in();
      }
      else{
        btn_Jky(5);
        jkyC1();
        C1_middle();  //print on display F1_rock
      }
      break;

    case ring:
      if(swbtn_state==5){ //s'ha de canviar!!
        C1_ring_in();
      }
      else{
        btn_Jky(5);
        jkyC1();
        C1_ring();  //print on display F1_rock
      }
      break;
    
    case pinky:
      if(swbtn_state==5){ //s'ha de canviar!!
        C1_pinky_in();
      }
      else{
        btn_Jky(5);
        jkyC1();
        C1_pinky();  //print on display F1_rock
      }
      break;

    case wrist:
      if(swbtn_state==5){ //s'ha de canviar!!
        C1_wrist_in();
      }
      else{
        btn_Jky(5);
        jkyC1();
        C1_wrist();  //print on display F1_rock
      }
      break;

    case goBackC1:
        btn_Jky(0);
        jkyC1();
        C1_goBack();  //print on display F1_rock
      break;
  }
}

void setup(){
  u8g2.begin();
  u8g2_prepare();
  servo.begin();
  servo.setPWMFreq(Freq);
  pinMode(jky, INPUT_PULLUP);
  F1=rock;
  C1=thumb;
  M1=openClose;
  swbtn_state=0;
}

void loop(){ 
  modes_M1();
}

Creating an variable array in C++

#include<iostream>                //including input/output libarary
using namespace std;
int main(){                               //starting main function
int array_name[5];                   //defining a variable array of type integer with name "array_name" and size 5.
array_name[0]=2;                   //assigning value of 2 to  first element of array "array_name"
array_name[1]=3;                   
array_name[2]=4                      // assinging values to other elements of array using their index number
array_name[3]=12;
array_name[4]=33;

return 0;
}

> More steps

#c++ #web #rest

GitHub - an-tao/drogon: Drogon: A C 14/17 based HTTP web application framework running on Linux/macOS/Unix/Windows

https://github.com/an-tao/drogon

A Simple Binary Tree Implementation in C++

#include <stdio.h>
 
class Node
{
public:
    Node( int v )
    {
        data = v;
        left = 0;
        right = 0;
    }
 
    int data;
    Node* left;
    Node* right;
};
 
void Add( Node** root, Node* n )
{
    if ( !*root  )
    {
        *root = n;
        return;
    }
 
    if ( (*root)->data < n->data )
    {
        Add( &(*root)->right, n );
    }
    else
    {
        Add( &(*root)->left, n );
    }
}
 
void Print( Node* node )
{
    if ( !node )  return;   
    Print( node->left );
    printf( "value = %i\n", node->data );
    Print( node->right );
}
 
int main()
{
    Node* root = 0;
 
    Add( &root, new Node( 1 ) );
    Add( &root, new Node( 2 ) );
    Add( &root, new Node( -1 ) );
    Add( &root, new Node( 12 ) );
 
    Print( root );
    return 0;
}

  
#include <ESP8266WiFi.h>


// Set these to run example.
#define WIFI_SSID "SSID"
#define WIFI_PASSWORD "PASSWORD"

  // connect to wifi.
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.print("connecting");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }
  Serial.println();
  Serial.print("connected: ");
  Serial.println(WiFi.localIP());

firebase basics

include <FirebaseArduino.h>

#define FIREBASE_HOST "example.firebaseio.com"
#define FIREBASE_AUTH "token_or_secret"


void setup() {
  Serial.begin(9600);
  Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH);
}

int n = 0;

void loop() {

  // set value
  Firebase.setFloat("number", 42.0);
  // handle error
  if (Firebase.failed()) {
      Serial.print("setting /number failed:");
      Serial.println(Firebase.error());  
      return;
  }
  delay(1000);
  
  // update value
  Firebase.setFloat("number", 43.0);
  // handle error
  if (Firebase.failed()) {
      Serial.print("setting /number failed:");
      Serial.println(Firebase.error());  
      return;
  }
  delay(1000);

  // get value 
  Serial.print("number: ");
  Serial.println(Firebase.getFloat("number"));
  delay(1000);

  // remove value
  Firebase.remove("number");
  delay(1000);

  // set string value
  Firebase.setString("message", "hello world");
  // handle error
  if (Firebase.failed()) {
      Serial.print("setting /message failed:");
      Serial.println(Firebase.error());  
      return;
  }
  delay(1000);
  
  // set bool value
  Firebase.setBool("truth", false);
  // handle error
  if (Firebase.failed()) {
      Serial.print("setting /truth failed:");
      Serial.println(Firebase.error());  
      return;
  }
  delay(1000);

  // append a new value to /logs
  String name = Firebase.pushInt("logs", n++);
  // handle error
  if (Firebase.failed()) {
      Serial.print("pushing /logs failed:");
      Serial.println(Firebase.error());  
      return;
  }
  Serial.print("pushed: /logs/");
  Serial.println(name);
  delay(1000);
}

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