Check out example codes for "visual studio 2019 read and write text file c++". It will help you in understanding the concepts better.

Code Example 1

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(){
   fstream newfile;
   newfile.open("tpoint.txt",ios::out);  // open a file to perform write operation using file object
   if(newfile.is_open()) //checking whether the file is open
   {
      newfile<<"Tutorials point \n";   //inserting text
      newfile.close();    //close the file object
   }
   newfile.open("tpoint.txt",ios::in); //open a file to perform read operation using file object
   if (newfile.is_open()){   //checking whether the file is open
      string tp;
      while(getline(newfile, tp)){ //read data from file object and put it into string.
         cout << tp << "\n"; //print the data of the string
      }
      newfile.close(); //close the file object.
   }
}

Learn ReactJs, React Native from akashmittal.com