#include int main(){ int n,i,flag=1; scanf("%d",&n); for(i=2;i if(n%i == 0) { flag=0; break; } if(flag) printf("%d is a prime\n",n); else printf("%d isn`t a prime\n",n); return 0;}
示例运行结果：
29
29 is a prime
25
25 isn`t a prime
