Program to Find Second Last Number in the Given Sequence till -1 in C++

#include<iostream.h>
using namespace std;
int main(int argc, char const *argv[])
{
    int num=0,prev_max=-1,max=0;

    while(num!=-1){
         cout<<"\n Enter Number\n";
        cin>>num;
        if(num>=max){
            prev_max=max;
            max=num;

        }
        else{
            if (num>=prev_max && num<=max)
            {

                prev_max=num;
            }
        }
           
    }
    cout<<"\n Second highest Max is "<<prev_max;

    return 0;
}