百练 3177 判决素数个数

题目链接：http://bailian.openjudge.cn/practice/3177

# include <stdio.h>int main(){int i,j,t,sum=0;int a,b;scanf("%d%d",&a,&b);if(a>b){t=a;a=b;b=t;}for(j=a;j<=b;j++){for(i=2;i<j;i++)if(j%i==0)break;if(i==j)sum++;}printf("%d\n",sum);return 0;}