cpp check if file opened code example

Example 1: c++ check if file exits

#include <fstream>
#include<iostream>
using namespace std;
int main() {
   /* try to open file to read */
   ifstream ifile;
   ifile.open("b.txt");
   if(ifile) {
      cout<<"file exists";
   } else {
      cout<<"file doesn't exist";
   }
}

Example 2: how to check if file is opened c++

ifstream file;
file.open(argv[1]);
if (!file.is_open()) { 
  cerr << "File did not open";
  exit(1); 
}