Input File Stream

std::ifstream reads data from an existing file.

input_file_stream.cpp

#include <cstdio>
#include <fstream>
#include <iostream>
#include <string>

int main() {
    std::string firstLine = ;
    std::string filename = "input_lines.txt";

    std::ofstream setup(filename);
    setup << firstLine << std::endl;
    setup << "omega" << std::endl;
    setup.close();

    std::ifstream input(filename);
    std::string line;
    int count = 0;

    while (std::getline(input, line)) {
        ++count;
        std::cout << "line" << count << "=" << line << std::endl;
    }

    std::cout << "count=" << count << std::endl;
    std::remove(filename.c_str());
    return 0;
}

#include <cstdio>
#include <fstream>
#include <iostream>
#include <string>

int main() {
    std::string firstLine = ;
    std::string filename = "input_lines.txt";

    std::ofstream setup(filename);
    setup << firstLine << std::endl;
    setup << "omega" << std::endl;
    setup.close();

    std::ifstream input(filename);
    std::string line;
    int count = 0;

    while (std::getline(input, line)) {
        ++count;
        std::cout << "line" << count << "=" << line << std::endl;
    }

    std::cout << "count=" << count << std::endl;
    std::remove(filename.c_str());
    return 0;
}

#include <cstdio>
#include <fstream>
#include <iostream>
#include <string>

int main() {
    std::string firstLine = ;
    std::string filename = "input_lines.txt";

    std::ofstream setup(filename);
    setup << firstLine << std::endl;
    setup << "omega" << std::endl;
    setup.close();

    std::ifstream input(filename);
    std::string line;
    int count = 0;

    while (std::getline(input, line)) {
        ++count;
        std::cout << "line" << count << "=" << line << std::endl;
    }

    std::cout << "count=" << count << std::endl;
    std::remove(filename.c_str());
    return 0;
}

input file stream An input file stream reads lines or tokens from a file with the same tools used for other streams.