Question

In the Source Folder (src) of this project create a new C source file called "gcd.c". Once again, copy the contents of the "main.c" file above into the "gcd.c" source file. Modify this program to NOT ask the user to input the second Positive Integer, if the user has entered a program terminating value for the "first" input Postitive Integer.

#include <stdlib.h>
#include <stdio.h>

int main(int argc, char *argv[]) {
//==============================
        setbuf(stdout, NULL);           // turns standard output buffering off

        int i;                          // Loop conter/index.
    int a;                          // The first number entered
    int b;                          // The second number entered.
    int gcd = -1;                               // GCD of "a" and "b". Initialized to -1 only for the purpose of viewing in debugger.

                                                                // Read an integer from the keyboard.
    printf("\n");
    printf("Enter the first  Positive Integer [0 to quit]: ");
        fflush(stdout);                 // Only required for GDC debugger to process input!
    scanf("%d", &a);

    printf("Enter the second Positive Integer [0 to quit]: ");
        fflush(stdout);                 // Only required for GDC debugger to process input!
    scanf("%d", &b);

    while ( (a >= 1) && (b >= 1) ) {
                                                                        // Calculate the "gcd" of the two entered values.
        for (i=1; i<=a && i<=b; i++) {
                                                                        // Check if "i" is a factor of both integers
                                                                        // and keep the largest one!
                if ( (a%i == 0) && (b%i == 0) ) gcd = i;
        }

        printf("\n");
        printf("===> G.C.D. of %d and %d is: [%d]\n", a, b, gcd);
        printf("\n");
                                            // Read the next pair of integers.
        printf("Enter the first  Positive Integer [0 to quit]: ");
        fflush(stdout);                     // Only required for GDC debugger to process input!
        scanf("%d", &a);

        printf("Enter the second Positive Integer [0 to quit]: ");
                fflush(stdout);                     // Only required for GDC debugger to process input!
        scanf("%d", &b);
    }
    printf(":::\n");
    printf("::: Program Terminated.\n");
    printf(":::\n");
    return 0;
}

The program output should look like the following:

Enter the first  Positive Integer [0 to quit]: 0
:::
::: Program Terminated.
:::

Answer 1

Just add loop at line 39 line

it checks if a==0 then it continues to loop

code:

#include <stdlib.h>
#include <stdio.h>

int main(int argc, char *argv[]) {
//==============================
setbuf(stdout, NULL); // turns standard output buffering off

int i; // Loop conter/index.
int a; // The first number entered
int b; // The second number entered.
int gcd = -1; // GCD of "a" and "b". Initialized to -1 only for the purpose of viewing in debugger.

// Read an integer from the keyboard.
printf("\n");
printf("Enter the first Positive Integer [0 to quit]: ");
fflush(stdout); // Only required for GDC debugger to process input!
scanf("%d", &a);

printf("Enter the second Positive Integer [0 to quit]: ");
fflush(stdout); // Only required for GDC debugger to process input!
scanf("%d", &b);

while ( (a >= 1) && (b >= 1) ) {
// Calculate the "gcd" of the two entered values.
for (i=1; i<=a && i<=b; i++) {
// Check if "i" is a factor of both integers
// and keep the largest one!
if ( (a%i == 0) && (b%i == 0) ) gcd = i;
}

printf("\n");
printf("===> G.C.D. of %d and %d is: [%d]\n", a, b, gcd);
printf("\n");
// Read the next pair of integers.
printf("Enter the first Positive Integer [0 to quit]: ");
fflush(stdout); // Only required for GDC debugger to process input!
scanf("%d", &a);
  
if(a==0) //addes this loop
{
   continue;
       }
  
printf("Enter the second Positive Integer [0 to quit]: ");
fflush(stdout); // Only required for GDC debugger to process input!
scanf("%d", &b);
}
printf(":::\n");
printf("::: Program Terminated.\n");
printf(":::\n");
return 0;
}