验证哥德巴赫猜想

/*验证Goldbach猜想*/

#include <stdio.h>

int main ()
{
printf ("Function : Verify the Goldbach Conjecture.\n");

int a, b, i, j, num;

printf ("Please input a number:\n");
scanf ("%d",&num);

if( num <= 2 || num % 2 != 0)
printf ("Error:Number inputed > 2 && Even number\n");
else
{
for (i = 3;i <= num; i++)
{
j = num - i;       //分成两数之和
a = primenum (i);  //判断是否为素数
b = primenum (j);

if (a && b)        //都是素数则满足哥德巴赫猜想
printf ("Goldbach Right! %d = %d + %d\n",num,i,j);
}

return 0;
}
}

//判断是否为素数，是返回1，不是返回0
primenum ( int m)
{
int k, n;
k = m / 2;

for (n = 2;n <= k; n++)
{
if (m % n == 0)
{
return 0;
break;
}
else if (n != k)
continue;

return 1;
}
}