gen2.cpp

/*
    Gen 4kk int / long long / double and write to file

    File: gen2.cpp

    Command: c++ -std=c++14 -O2 -Wall -Wextra -pedantic -Wconversion -Wshadow -fmax-errors=1 gen2.cpp -o gen2.exe

*/

#include <stdio.h>
#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstdlib>
#include <ctime>
#include <cassert>
#include <vector>

typedef long long ll;

ll get_ll() {
    ll answ = 0;
    for (int i = 0; i < 6; ++i) (answ *= 1000) += std::rand() % 1000;
    assert(0 <= answ && answ <= 1e18L);
    return answ;
}

int main() {
    const int n = 4*1000*1000;

    // Gen vector of 4kk integers:
    std::vector<int> arr_int(n);
    for (auto& it : arr_int) {
        it = int(get_ll() % (int)1e9);
    }

    // Gen vector of 4kk long long:
    std::vector<ll> arr_ll(n);
    for (auto& it : arr_ll) {
        it = get_ll();
    }

    // Gen vector of 4kk double:
    std::vector<double> arr_dbl(n);
    for (auto& it : arr_dbl) {
        it = (double)get_ll() / 1e9;
    }

    double time[4][3] = {}; std::ofstream fout;
    // --- ofstream output
    // Write vector of integers:
    double t = clock();

    fout.open("file_int.txt");

    fout << arr_int.size() << '\n';
    for (auto& it : arr_int) fout << it << ' ';
    fout << '\n';

    fout.close();

    time[2][0] = (clock() - t) / CLOCKS_PER_SEC;

    // Write vector of long longs:
    t = clock();

    fout.open("file_ll.txt");

    fout << arr_ll.size() << '\n';
    for (auto& it : arr_ll) fout << it << ' ';
    fout << '\n';

    fout.close();

    time[2][1] = (clock() - t) / CLOCKS_PER_SEC;

    // Write vector of doubles:
    t = clock();

    fout.open("file_dbl.txt");

    fout << arr_dbl.size() << '\n';
    for (auto& it : arr_dbl) fout << it << ' ';
    fout << '\n';

    fout.close();

    time[2][2] = (clock() - t) / CLOCKS_PER_SEC;

    // --- ifstream input
    // Input vector of integers:
    t = clock();
    std::ifstream fin("file_int.txt");

    int size; fin >> size;
    std::vector<int> temp_int(size);
    for (auto& it : temp_int) {
        fin >> it;
    }
    fin.close();
    time[0][0] = (clock() - t) / CLOCKS_PER_SEC;

    // Input vector of long long:
    t = clock();
    fin.open("file_ll.txt");

    fin >> size;
    std::vector<ll> temp_ll(size);
    for (auto& it : temp_ll) {
        fin >> it;
    }
    fin.close();
    time[0][1] = (clock() - t) / CLOCKS_PER_SEC;

    // Input vector of doubles:
    t = clock();
    fin.open("file_dbl.txt");

    fin >> size;
    std::vector<double> temp_dbl(size);
    for (auto& it : temp_dbl) {
        fin >> it;
    }
    fin.close();
    time[0][2] = (clock() - t) / CLOCKS_PER_SEC;

    // scanf / printf input
    t = clock();
    auto file = fopen("file_int.txt", "rt");
    fscanf(file, "%d", &size);
    temp_int.resize(size);
    for (auto& it : temp_int) fscanf(file, "%d", &it);
    fclose(file);
    time[1][0] = (clock() - t) / CLOCKS_PER_SEC;

    t = clock();
    file = fopen("file_ll.txt", "rt");
    fscanf(file, "%d", &size);
    temp_ll.resize(size);
    for (auto& it : temp_ll) fscanf(file, "%lld", &it);
    fclose(file);
    time[1][1] = (clock() - t) / CLOCKS_PER_SEC;

    t = clock();
    file = fopen("file_dbl.txt", "rt");
    fscanf(file, "%d", &size);
    temp_dbl.resize(size);
    for (auto& it : temp_dbl) fscanf(file, "%lf", &it);
    fclose(file);
    time[1][2] = (clock() - t) / CLOCKS_PER_SEC;

    // scanf / printf output
    t = clock();
    file = fopen("file_int.txt", "wt");
    fprintf(file, "%d\n", size);
    temp_int.resize(size);
    for (auto& it : temp_int) fprintf(file, "%d", it);
    fclose(file);
    time[3][0] = (clock() - t) / CLOCKS_PER_SEC;

    t = clock();
    file = fopen("file_ll.txt", "wt");
    fprintf(file, "%d\n", size);
    temp_ll.resize(size);
    for (auto& it : temp_ll) fprintf(file, "%lld", it);
    fclose(file);
    time[3][1] = (clock() - t) / CLOCKS_PER_SEC;

    t = clock();
    file = fopen("file_dbl.txt", "wt");
    fprintf(file, "%d\n", size);
    temp_dbl.resize(size);
    for (auto& it : temp_dbl) fprintf(file, "%f", it);
    fclose(file);
    time[3][2] = (clock() - t) / CLOCKS_PER_SEC;
    std::cout << "\n---------- Cygwin x64 8.1 - 4kk I/O speed test --------";
    std::cout << "\n-------------------------------------------------------";
    std::cout << "\n     type | ifstream |    scanf | ofstream |   printf |";
    std::cout << "\n-------------------------------------------------------";
    std::cout << "\n      int |"; for (int i = 0; i < 4; ++i) std::cout << std::setprecision(3) << std::setw(9) << std::fixed << time[i][0] << " |";
    std::cout << "\nlong long |"; for (int i = 0; i < 4; ++i) std::cout << std::setprecision(3) << std::setw(9) << std::fixed << time[i][1] << " |";
    std::cout << "\n   double |"; for (int i = 0; i < 4; ++i) std::cout << std::setprecision(3) << std::setw(9) << std::fixed << time[i][2] << " |";
    std::cout << "\n-------------------------------------------------------";
    std::cout << std::endl;


    return 0;
}