Thread: Goldbach's conjecture

Hey guys:

One of the assignment for class is Goldbach's conjecture. Below is my code, but I am having problems with the actually computation. It goes into an infinite loop when it prints the first conjecture which is 4 =2 +2. To me, it doesn't seem like my code would do that, but obviously it does.

Can someone help me out and figure out why it's going to an infinite loop?

Thanks

Code:

#include<stdio.h>
#include<stdbool.h>


bool is_prime(int );

void goldbach(int n, int m)
{
  int i, j, k;


  for(i=n; i<= m; i+2)
    {
      for(j=2; j<= m; j++)
        {
          if(is_prime(j))
            {
              for(k=2; k<= m; k++)
                {
                  if(is_prime(k))
                    {
                      if( i == (j + k))
                        printf("&#37;d = %d + %d\n", i, j, k);

                    }
                }
            }
        }
    }


}

bool is_prime(int j)
{
  int divisor;

  for(divisor = 2; divisor*divisor <= j; divisor++)
    {
      if(j % divisor == 0)
        return false;
    }

  return true;

}

int main(void)
{

  int i, j, n, m;

  printf("\nEnter the value of n: ");
  scanf("%d", &n);

  printf("Enter the value of m: ");
  scanf("%d", &m);


  /* ********** SETS BOUNDRIES CORRECTLY ********** */

  if(n < 4)
      n = 4;

  if((n % 2) != 0)
      n = n + 1;

  if((m % 2) != 0)
    m = m - 1;

  /* ********************************************* */


  goldbach( n, m);

  printf("\n");



  return(0);
}