C++ File I/O Operation

fileio.cpp

#include <sstream>
#include <iostream>
#include <fstream>
using namespace std;

int main () {
  ofstream Finput;
  Finput.open ("file.txt");
  
  char str[100];
  
  cout<<"Enter String : ";
  cin.getline(str,sizeof(str));
  
  Finput << str;
  Finput.close();
  
  std::ifstream infile("file.txt");
  std::string line;
  while (std::getline(infile, line)){
        std::istringstream iss(line);
        int a, b;
        if (!(iss >> a >> b)) { break; }
  }
  cout<<line;
  
  //system("pause");
  return 0;
}