các tính năng của hàm string

Thu Aug 19 2021 02:44:08 GMT+0000 (UTC)

Saved by @_Ryan_ #c

```#include<stdio.h>
#include<stdbool.h>
#include<conio.h>
#include<math.h>
#include<string.h>

void main()
{
int choice;
int choose;
char str1[20], str2[20];

printf("enter string 1: ");
gets(str1);
printf("enter string 2: ");
gets(str2);

do
{
printf("\n");
printf("==========================\n");
printf("= 1. compare two strings =\n");
printf("= 2. copy string         =\n");
printf("= 3. concatenation       =\n");
printf("= 4. exit                =\n");
printf("==========================\n");

printf("choice: ");
scanf("%d", &choice);
int result;

switch(choice)
{
case 1:
result = strcmp(str1, str2);
if(result == 0)
{
printf("two strings is equal");
}
if (result > 0)
{
printf("string 1 > string 2");
}
else
{
printf("string 1 < string 2");
}
break;
case 2:
printf("you wants copy string 1 into 2(input: 1)or 2 into 1(input 2) ?\n");
printf("choose: ");
scanf("%d", &choose);
if(choose == 2)
{
strcpy(str1, str2);
printf("string 2: ");
puts(str2);
printf("string 1: ");
puts(str1);

}
else
{
strcpy(str2, str1);
printf("string 2: ");
puts(str2);
printf("string 1: ");
puts(str1);
}
break;
case 3:
printf("you wants concatenation string 1 into 2(input: 1)or 2 into 1(input 2) ?\n");
printf("choose: ");
scanf("%d", &choose);
if(choose == 2)
{
strcat(str1, str2);
printf("string 1:");
puts(str1);
}
else
{
strcat(str2, str1);
printf ("string 2: ");
puts(str2);

}
break;
default :
exit(0);
break;
}

}while( choice <= 3);

getch();

}```
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