P124.41

#include<stdio.h>#include<math.h>#include<conio.h>int prim(int num){int i=2,isprime=1;int a=sqrt(num);while(i<=a){if(num%i==0){isprime=0;break;}i++;} return isprime;}int main(){int x,i;while(1){printf("input number");scanf("%d",&x);if((x%2==1)||x<4){printf("不是大于4的偶数");return 0;}for(i=2;i<=x/2;i++){if(prim(i)&&prim(x-i))printf("%d=%d+%d\n",x,i,x-i);}}return 0;}