Basic File Input and Output

Snippet

Basic File Input and Output

C++ provides fstream for file operations. ofstream creates and writes to files, while ifstream reads from files. Always check if a file opened successfully using is_open(), and close files when done to free system resources.

snippet.cpp
cpp
#include <iostream>
#include <fstream>
#include <string>
 
int main() {
    std::ofstream outFile("data.txt");
    
    if (outFile.is_open()) {
        outFile << "Hello, World!" << std::endl;
        outFile << "C++ file handling" << std::endl;
        outFile.close();
        std::cout << "File written successfully!" << std::endl;
    }
    
    std::ifstream inFile("data.txt");
    std::string line;
    
    if (inFile.is_open()) {
        while (std::getline(inFile, line)) {
            std::cout << line << std::endl;
        }
        inFile.close();
    }
    
    return 0;
}

Breakdown

std::ofstream outFile("data.txt");

Creates an output file stream to write to 'data.txt'

outFile.is_open()

Checks if the file was successfully opened

outFile << "Hello, World!"

Writes text to the file using the stream operator

std::ifstream inFile("data.txt");

Creates an input file stream to read from 'data.txt'

std::getline(inFile, line)

Reads one line at a time from the file into the string

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Basic File Input and Output

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