代码解释，对每一行代码进行解释

#include<stdio.h>void prime(int x){ int i; for(i=2;i<x;i++) if(x%i==0)break; if(i<x) printf("This is not a prime!"); else printf("This is a prime!");}int main(){ int a; scanf("%d",&a); prime(a); return 0;}