ofstream से फ़ाइलें लिखना

#include <iostream>
#include <fstream>

int main() {
    std::ofstream("t.txt") << "old content\n";
    std::ofstream out("t.txt");
    out << "new content\n";
    std::ifstream in("t.txt");
    std::string line; std::getline(in, line);
    std::cout << line << '\n';
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    std::ofstream("log.txt") << "line1\n";
    std::ofstream out("log.txt", std::ios::app);
    out << "line2\n";
    out.close();
    std::ifstream in("log.txt");
    std::string l; int n = 0;
    while (std::getline(in, l)) ++n;
    std::cout << n << " lines\n";
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    std::ofstream out("ok.txt");
    if (!out) {
        std::cout << "failed to open\n";
        return 1;
    }
    out << "safe write\n";
    std::cout << "write ok\n";
    return 0;
}

#include <iostream>
#include <fstream>
#include <iomanip>

int main() {
    std::ofstream out("pi.txt");
    out << std::fixed << std::setprecision(3) << 3.14159 << '\n';
    out.close();
    std::ifstream in("pi.txt");
    std::string s; in >> s;
    std::cout << s << '\n';
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    std::ofstream out("squares.txt");
    for (int i = 1; i <= 5; ++i) out << i << ' ' << i * i << '\n';
    out.close();
    std::cout << "wrote 5 rows\n";
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    std::ofstream out("flush.txt");
    out << "important" << std::flush;
    std::cout << "flushed to disk\n";
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    std::ofstream out("nl.txt");
    out << "fast\n";          // newline only
    out << "slow" << std::endl; // newline + flush
    std::cout << "both written\n";
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    {
        std::ofstream out("rt.txt");
        out << 7 << ' ' << 8 << '\n';
    }
    std::ifstream in("rt.txt");
    int a, b; in >> a >> b;
    std::cout << a + b << '\n';
    return 0;
}

#include <iostream>
#include <fstream>

int main() {
    std::ofstream out("modes.txt", std::ios::out | std::ios::trunc);
    out << "fresh\n";
    std::cout << "opened with explicit modes\n";
    return 0;
}