Динамические массивы

#include <iostream>

using namespace std;

void task_arr_vs_pointer();
void task_dynamic_array();


void task4() {
    double arr[]{ 21.5, 25.6, 36.6, 37.2 };
    for (int k = 0; k < 4; k++) {
        cout << *(arr+k) << endl;
    }
    cout << endl;
}

void task5() {
    int* pArr = new int[4]{ 1,2,3,4 };
    for (int k = 0; k < 4; k++)
        cout << pArr[k] << endl;
    delete[] pArr;

    int pArr2[]{1, 2, 3};
    pArr = pArr2;
}

void calc_statistic(int size, int* arr,
    int& positives,
    int& zeros,
    int& negatives
    ) {
    positives = 0;
    zeros = 0;
    negatives = 0;
    for (int k = 0; k < size; k++) {
        if (arr[k] < 0)
            negatives++;
        else if (arr[k] > 0)
            positives++;
        else
            zeros++;
    }
}

void task2() {
    //int arr[]{ -3, -2, -1, 0, 1, 3, 0, 5 };
    int* arr = new int[] {-3, -2, -1, 0, 1, 3, 0, 5};
    int n, p, z;
    calc_statistic(8, arr, p,z,n);

    cout << "pos: " << p << "\n"
        << "neg: " << n << "\n"
        << "zer: " << z << endl;

    delete[] arr;
}

void get_sum_and_prod(
    int size,
    int* arr,
    int& sum,
    int& prod
) {
    sum = 0;
    prod = 1;

    //sum = arr[0] + arr[1] + arr[2] + ... + arr[size - 1];
    //pord = arr[0]*arr[1]* ... arr[size-2]*arr[size-1]

    for (int k = 0; k < size; k++) {
        sum += arr[k];
        prod *= arr[k];
    }
}

void task1() {
    int arr[]{ 1,2,3,4,5,6,7 };
    int prod, sum;
    get_sum_and_prod(7, arr, sum, prod);

    cout << "sum: " << sum << "\n"
        << "prod: " << prod << endl;
}

int main() {
    //task4();
    //task_arr_vs_pointer();
    task2();
    return 0;
}

void task_arr_vs_pointer() {
    int arr[]{ 17,2,3,4 };
    cout << arr << endl;
    cout << &(arr[0]) << endl;
    cout << &(arr[1]) << endl;
    cout << &(arr[2]) << endl;

    cout << arr << endl;
    cout << arr+1 << endl;
    cout << arr+2 << endl;

    // arr[k] почти тоже самое, что *(arr + k)

    cout << *(arr) << endl;
    cout << *(arr + 1) << endl;
    cout << *(arr + 2) << endl;

    cout << *arr << endl;
}

void task_dynamic_array() {
    // static
    const int sn = 5;
    int static_arr[sn]{};
    static_arr[1] = 17;
    cout << static_arr[2] << endl;

    // dynamic
    int dn = 10;
    int* dynamic_arr = new int[dn] {};
    dynamic_arr[1] = 17;
    cout << dynamic_arr[2] << endl;
    delete[] dynamic_arr;

}