Lab for Bezus №4 (9 var)

#include<iostream>
#include<fstream>
#include<string>

using namespace std;

string changeS(string s1)
{
    int size = s1.size() - 3;
    string s2 = s1.substr(0, size);
        s2 = s2 + "***";
    return s2;
}

int main()
{
    cout << "Input a word range>";
    int range;
    cin >> range;

    ifstream fileIn;
    fileIn.open("input.txt");
    if (!fileIn.is_open())
        cout << "Error, file 'intput.txt' not found";


    ofstream fileOut;
    fileOut.open("output.txt");
    //if (!fileOut.open)
    //  cout << "Error, file 'output.txt' not found";

    string s1;
    string s2;

    while (!fileIn.eof())
    {
        fileIn >> s1;
        if (s1.size() > range)
            s2 = changeS(s1);
        else
            s2 = s1;
        fileOut << s2 + ' ';
    }
    fileIn.close();
    fileOut.close();

    return 0;
}