Inertial Observer - 7 months ago 39

C Question

This program tests Goldbach's Conjecture, printing a given even integer as the sum of two primes. After printing the first one, the given integer is to iterate by 2 , then find the sum of two primes for that integer. And so on until the program is interrupted by the user.

This problem is that the program prints a '0' after every executed print statement.

The code:

`#include <stdio.h>`

#include <math.h>

int GC(int goldsum); //function prototype

int main()

{

int goldsum;

printf("Enter an even integer greater than 5: ");

scanf("%d", &goldsum);

printf("%d\n", GC(goldsum));

goldsum = goldsum + 2;

printf("%d\n", GC(goldsum));

}

int GC(int goldsum) //function definition

{

int i, j; //prime addends

int div1, div2; //divisors

char prime1, prime2;

for (i=2 ;i<goldsum ;i++) //when number is less than goldsum, run this loop iterating by 1

{

prime1 = 1;

for (div1=2 ;div1<i ;div1++) //this loop determines if "i" is prime.

if (i % div1 == 0) //if yes, the prime number is stored in "i"

prime1 = 0;

if (prime1)

{

for (j=3; j<goldsum; j+=2) //when number is less than goldsum, run this loop iterating by 2

{

prime1 = 1;

for (div2=2; div2<j; div2++) //this loop determines if "j" is prime.

if(j % div2 == 0) //if yes, the prime number is stored in "j"

prime1 = 0;

if (prime1)

if (i + j == goldsum) //If i + j = goldsum, it prints the result.

{

printf("%d + %d = %d\n",i ,j , goldsum);

return 0;

}

}

}

}

return 0;

}

The output:

`Enter an even integer greater than 5: 10`

3 + 7 = 10

0

5 + 7 = 12

0

What I want it to look like:

`Enter an even integer greater than 5: 10`

3 + 7 = 10

5 + 7 = 12

Source (Stackoverflow)