为什么输出不了结果？调试也看不懂是哪里出错了？

Question

输出1~100间的质数

int main(int argc, char** argv) { 
   int i=1,j=0,flag=1;
    while(i<=100)
    {
        while(j<=sqrt(i))
        {
            if(i%j==0)
            {
                flag=0;
            }
            j++;
        }
        if(flag)
        {
            cout<<i<<" ";
        }
        i++;
     } 
    return 0;
}

Answer 1

#include<iostream>
#include<cmath>
using namespace std;
int main(int argc, char** argv) { 
   int i=1,j=0,flag;
    while(i<=100)
    {
        flag = 1;
        j = 2;
        while(j<=sqrt(i))
        {
            if(i%j==0)
            {
                flag=0;
            }
            j++;
        }
        if(flag)
        {
            cout<<i<<" ";
        }
        i++;
     } 
    return 0;
}