#include<stdio.h> #include<math.h> int zhi(int num) { int m = sqrt(num); for (int i = 2; i <= m; i++) { if (num%i == 0) return 0; } return 1; } void qh(int num){ //m是i所能达到的最大值 怎样求出k那?//int m = num / 2; int k = 0; for (int i = 0; i < m; i++){ k = num - i; if (zhi(k) && zhi(i)) { printf("%d=%d,%d", num, i, k); } }} void main() { int a=4; printf("%d ", zhi(a)); qh(10); system("pause"); }From:csdn博客 han1558249222