Memory

#include <iostream>
#include <random>
#include "windows.h"

const size_t SIZE_ARR = 800; //change for bigger memory size (800 = 2GB)

int*** createMatrix() {

    std::mt19937 gen(time(0));
    std::uniform_int_distribution<int> randomNum(0, 9);

    int*** arr3D = new int** [SIZE_ARR] {}; // for 3 pointers -> 2D
    for (int i = 0; i < SIZE_ARR; ++i) {

        arr3D[i] = new int* [SIZE_ARR] {};  // for 3 x 3 pointers -> 1D
        for (int j = 0; j < SIZE_ARR; ++j) {

            arr3D[i][j] = new int[SIZE_ARR] {}; // for each 1D pointer
            for (int k = 0; k < SIZE_ARR; ++k) {
                arr3D[i][j][k] = randomNum(gen);
            }
        }
    }
    return arr3D;
}

void releaseMemory(int*** arr3D) {
    for (int i = 0; i < SIZE_ARR; ++i) {
        for (int j = 0; j < SIZE_ARR; ++j) {
            delete[] arr3D[i][j]; // delete 1D arrays
            arr3D[i][j] = nullptr;
        }
        delete[] arr3D[i]; // delete 3 x 2D array
        arr3D[i] = nullptr;
    }
    delete[] arr3D; // delete the 3D array
    arr3D = nullptr;
}

void printMemoryUsage(MEMORYSTATUSEX memInfo) {
    GlobalMemoryStatusEx(&memInfo);
    DWORDLONG totalPhysMem = memInfo.ullTotalPhys;
    DWORDLONG physMemUsed = memInfo.ullTotalPhys - memInfo.ullAvailPhys;
    totalPhysMem = totalPhysMem / 1024; // in kb
    physMemUsed = physMemUsed / 1024; // in kb
    std::string totalMemoryBar(50, '|'); // 50 x | represent 100% of the memory
    std::string usedMemoryBar(((double)physMemUsed / totalPhysMem) * 100 / 2, '|');
    std::cout << " RAM total:" << totalMemoryBar << ' ' << totalPhysMem << " Kb" << std::endl;
    std::cout << " RAM used: "<< usedMemoryBar << ' ' << physMemUsed << " Kb" << std::endl;
    std::cout << " RAM used: " << ((double)physMemUsed / totalPhysMem) * 100 << " %" << std::endl;
}

int main()
{
    MEMORYSTATUSEX memInfo;
    memInfo.dwLength = sizeof(MEMORYSTATUSEX);
    std::cout << " Current memory status: " << std::endl;
    printMemoryUsage(memInfo);
    std::cout << std::endl;

    std::cout << " Size of the 3D int matrix: " << SIZE_ARR << std::endl;
    std::cout << " Requested memory: ~" << SIZE_ARR * SIZE_ARR * SIZE_ARR * 4 / 1000 / 1000 // int = 4 byte
              << " MB"<< std::endl;
    std::cout << " Allocation of memory . . . " << std::endl;
    int*** arr3D = createMatrix();
    printMemoryUsage(memInfo);
    std::cout << std::endl;

    std::cout << " Deallocation of memory . . . " << std::endl;
    releaseMemory(arr3D);
    std::cout << " Current memory status: " << std::endl;
    printMemoryUsage(memInfo);

    return 0;
}