我数学忘光了,哈哈...

呵呵，挺逗的。想法还是有的。

#include <iostream.h>
int main() {
    int n, prime, k;
    for(n = 100; n <= 200; n++) {
        prime = 1;
        for(k = 2; k <= n / 2; k++) {
            if(n % k == 0) prime = 0;
            break;
        }
        if(prime) cout<<n<<endl;
    }
    return 0;
}

#include <iostream>
using namespace std;

int main()
{
    int i, j, t;
    for (i = 100; i < 201; i++)
    {
        t = 0;
        for (j = 2; j < i; j++)
        {
            if (i%j == 0)
            {
                t++;
                break;
            }

        }
        if (t == 0)
            cout<<i <<endl;
    }

    return 0;
}

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

}
任意数之间的素数