Brzesko

#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int main()
{

    string filename,data,c1,c2,line;

    cin>>filename;
    cin>>c1;
    cin>>c2;


    string nfilename=filename;
    int txtPosition=nfilename.find(".txt");
    nfilename.replace(txtPosition,txtPosition+4,"_nowy.txt");


    ifstream file(filename.c_str());;
    if(!file.good())
        return -1;

    // Wczytanie tekstu z pliku do zmiennej data
    while ( getline (file,line) ){
      data=line;
    }

    file.close();

    //Zamiana ciagu c1 na c2
    int occurence=data.find(c1);
    while(occurence!=string::npos){
        data.erase(occurence,c1.size());
        data.insert(occurence,c2);
        occurence=data.find(c1,occurence+1);
    }

    //Utworzenie nowego pliku
    ofstream newfile(nfilename.c_str());
    newfile<<data;
    newfile.close();



    return 0;
}