How to Read and Write Arrays to/from Files in C++?

How to Redirect cin and cout to Files in C++?

Last Updated : 30 Jan, 2024

In C++, we often ask for user input and read that input using the cin command and for displaying output on the screen we use the cout command. But we can also redirect the input and output of the cin and cout to the file stream of our choice.

In this article, we will look at how to redirect the cin and cout to files in C++.

Redirecting cin and cout to a File in C++

For redirecting cin and cout to a file, we first create the input file stream and output file stream to our desired file. Then using rdbuf() function of stream objects, we redirect the input for cin to the file and output for cout to the file.

C++ Program to Redirect cin and cout to a File

C++

// C++ program to redirect cin and cout to files
#include <fstream>
#include <iostream>

using namespace std;

int main()
{
    // Opening the input file stream and associate it with
    // "input.txt"
    ifstream fileIn("input.txt");

    // Redirecting cin to read from "input.txt"
    cin.rdbuf(fileIn.rdbuf());

    // Opening the output file stream and associate it with
    // "output.txt"
    ofstream fileOut("output.txt");

    // Redirecting cout to write to "output.txt"
    cout.rdbuf(fileOut.rdbuf());

    // Variables for input
    int x, y;
    // Reading two integers from "input.txt"
    cin >> x >> y;
    // Writing the product of the two integers to
    // "output.txt"
    cout << "Product: " << (x * y) << endl;

    return 0;
}

input.txt

10 20

output.txt

How to Read and Write Arrays to/from Files in C++?

rajveer810214

Improve

Article Tags :

Practice Tags :

CPP

Similar Reads

How to Open and Close a File in C++?

In C++, we can open a file to perform read and write operations and close it when we are done. This is done with the help of fstream objects that create a stream to the file for input and output. In this article, we will learn how to open and close a file in C++. Open and Close a File in C++ The fst

How to Read and Write Arrays to/from Files in C++?

In C++, an array is a collection of elements of the same type placed in contiguous memory locations. A file is a container in a computer system for storing information. In this article, we will learn how to read and write arrays to/from files in C++. Example: Input: Array = {1, 2, 3, 4, 5}Output: //

How to Read From a File in C++?

Reading from a file means retrieving the data stored inside a file. C++ file handling allows us to read different files from our C programs. This data can be taken as input and stored in the program for processing. Generally, files can be classified in two types:Text File: Files that contains data i

How to Use cin.fail() Method in C++?

In C++, the cin.fail() method is a part of <iostream> library that is used to check whether the previous input operation has succeeded or not by validating the user input. In this article, we will learn how to use cin.fail() method in C++. Example: Input: Enter an integer: aOutput: Invalid Inp

How to Read a File Line by Line in C++?

In C++, we can read the data of the file for different purposes such as processing text-based data, configuration files, or log files. In this article, we'll learn how to read a file line by line in C++. Read a File Line by Line in C++We can use the std::getline() function to read the input line by

How to Extract File Name and Extension From a Path in C++?

Prerequisites: Install C++17 or Newer Standard Compiler It is a common requirement of users to extract filenames and their extensions from a given path. The process is trivial, but it becomes hard under some circumstances (different OS, file types, etc.). This article will teach you how to extract t

How to Create a Pointer to a Function in C++?

In C++, a function pointer is a variable that stores the address of a function that can later be called through that function pointer. It is useful for passing functions as parameters to other functions(callback functions) or storing them in data structures. In this article, we will learn how to use

How to Read a File Character by Character in C++?

In C++, file handling is used to store data permanently in a computer. Using file handling we can store our data in secondary memory (Hard disk). In this article, we will learn how to read a file character by character in C++. Example: Input: "Geeks for Geeks"Output: G e e k s f o r G e e k sRead Te

How to Compile C++ Code in macOS ?

Compiling a C++ code means translating the program from the human-readable form (high-level language) to something a machine can â€œunderstandâ€ (machine language) so that the program can run on a machine. In this article, we will learn how to compile C++ code in macOS. C++ Program Compilation in macOS

How to Convert a std::string to char* in C++?

In C++, strings are the textual data that is represented in two ways: std::string which is an object, and char* is a pointer to a character. In this article, we will learn how to convert a std::string to char* in C++. Example Input:string myString = "GeeksforGeeks";Output:char * myString = "Geeksfor