编辑代码

#include <stdio.h>
#define MAX 100000
int isPrime (int num) {
    int a = 0;
    for (int i=2; i <= num-1;i++){
        if (num % i == 0){
            a++;
            break;
        }
    }
    if (a==0){
        return 1;
    }else{
        return -1;
    }
}
int main () {
    int f[MAX]={};
    f[1] = 1;
    for(int i = 2 ; i < MAX; i++){
        if(isPrime(i) == 1){
            f[i] = f[i-1] + 1;    
        }else{
            f[i] = f[i-1];
        }
    }
    int m,n, count;
    while(scanf("%d%d",&m,&n)!=EOF){
        count = f[n] - f[m-1];
        printf("%d\n", count);
        count = 0;
    }
    
    return 0;
}