Help regarding Input/Output with File in C++.

please help me how to take input from .txt file in a program,and how to write output in a .txt file.

1 Like

Taking input from and writing output in .txt file in a c++ program is very simple,

just add these following two lines in the beginning of the main program.

    freopen("input.txt","r",stdin);//redirects standard input
    freopen("output.txt","w",stdout);//redirects standard output

Now, all input data will be taken from input.txt file

and all output data will be written into output.txt file.

sample program-

#include<iostream>
using namespace std;
int main()
{
    freopen("input.txt","r",stdin);//redirects standard input
    freopen("output.txt","w",stdout);//redirects standard output
    
    int x;
    cin>>x;//reads from input.txt
    cout<<x<<endl;//writes to output.txt
    return 0;
}

Hope ,this is helpful.

If you still don’t get anything ,feel free to ask.

The question has been asked before. Take a look here and here. Also check here. In my opinion stream redirection from the console is the easier way because the code does not need to be changed, however both will serve the purpose and what you prefer is your choice.

if you are using turbo c++ complier than follow the following steps:

  1. Use fstream.h header file (like : #include<fstream.h> )

  2. for save or give input into file

Example :

ofstream fo; // used to open files

fo.open(“Myfile.txt”,ios::out); //used to initialized file with any name

fo<<text<<"\n"; // Insert text or data

fo.close(); // used to close files

  1. for Print data from file

Example :

ifstream fi; // used to open files

fi.open(“Myfile.txt”,ios::in); //used to initialized file with any name

while(!fi.eof())

{

   fi>>text;  // Read text or data

   cout<<text;

}

fi.close(); // used to close files

It is Not in Details

if You want To See More Details

Right Click in Turbo c++ compiler

and type fstream (without click any more …)

now select fstream.h from options and read full details about this header file

and abouts its function

//