#include<stdio.h>


//change negative number to positive number
void change(float num1, float num2, float num3)
{
    printf("changed: [%.1f] [%.1f] [%.1f]", num1 * -1, num2 * -1, num3 * -1);
}
void main()
{
  float num1, num2, num3;
  printf("please enter negative numbers\n");
  
  //check input data 
  do 
  {
    printf("enter number 1: ");
    scanf("%f", &num1);
    printf("enter number 2: ");
    scanf("%f", &num2);
    printf("enter number 3: ");
    scanf("%f", &num3);

     if(num1 >= 0 || num2 >= 0 || num3 >= 0)
     {
      printf("please enter negative numbers\n");
     }
  }while(num1 >= 0);

  change(num1, num2, num3);
}