输入num值，求num以内最大质素

#include <iostream>

using namespace std;

int FindMaxZishu(int num)
{
    for(int right = num;right>0;right--)
    {
        bool flag=true;
        for(int i = 2;i<right-1;i++)
        {
            if(right%i == 0)
                flag=false;
        }
        if(flag&&right!=1)
        {
            return right;
        }
    }

}

int main(int argc, char *argv[])
{
    int num;
    cin>>num;
    cout<<FindMaxZishu(num)<<endl;
    return 0;
}