#include <iostream>
#include <fstream>
//#include <conio.h>
#include <cstdlib>
#include <string>
#include <sstream>
using namespace std;

int main()
{
    char user_info= ' ';
    string string_convert;
    int num1;
    bool bfail=true;


    do
    {
        bfail=true;
        cout << "Enter num1: ";
        while(user_info != '\n')
        {
            cin.get(user_info);
            if(isdigit(user_info))
                string_convert+=user_info;
            else if(user_info=='\n')
            {
             //   user_info=='\n';
                if(bfail==false)
                    string_convert="";
            }
            else
                bfail=false;
        }
        user_info=' ';
    }while(bfail!=true);
    cerr << "before convert: " << string_convert << endl;
    cout << "after convert: " << atoi(string_convert.c_str()) << endl;
    

    return 0;
}