View Code of Problem 27

#include<stdio.h>
#include<math.h>
int IsPrime(int num){
	int res;
	if(num < 2){
		res = 0;
	} //小于2必定不是素数 
	int bound = sqrt(num);
	for(int i=2; i<=bound; i++){
		if(num % i == 0){
			res = 0;
		}
	    res = 1;
	} //for
	
    return res;	
}

int main(){
    int a,b;
    int sum = 0;
    while(scanf("%d %d",&a,&b) != EOF) {
    	for(int i=a+1; i<b ;i++){
    		if (IsPrime(i)) {
    			sum += i;
			}
		}
		printf("%d\n",sum);
	}

	return 0;
}