//***************************************************//
//C语言验证歌德巴赫猜想的源代码 //
//***************************************************//
#include<stdio.h>
#include<math.h>
void main()
{
int i,j,num;
int p,q,flagp,flagq;
printf("Please input a plus integer:");
scanf("%d",&num);

//代码(num%2)!=0表示num不能被2整除
if(((num%2)!=0) || (num <= 4))
printf("input data error!\n");
else
{
p = 1;

//do-while循环体
do
{
p = p+1;
q = num - p;
flagp = 1;
flagq = 1;

//for循环体
for(i = 2;i <=(int)(floor(sqrt((double)(p))));i++)
{
if((p%i) == 0)
{
flagp = 0;
break;
}
}

//while循环体
j = 2;
while(j <= (int)(floor(sqrt((double)(q)))))
{
if ((q%j) == 0)
{
flagq = 0;
break;
}
j++;
}
}while (flagp*flagq == 0);

printf("%d = %d + %d \n",num,p,q);
}
}