my_lib.h

#pragma once

#include <iostream>

template<class Type>
int dsize(Type* a) {
    if (a)
        return _msize(a) / sizeof(Type);
    else
        return 0;
}

template<class Type>
void show_arr(int sz, Type* arr, char ch = ' ') {
    for (int k = 0; k < sz; ++k)
        std::cout << arr[k] << ch;
    std::cout << std::endl;
}

template <class Type>
bool append(Type*& arr, Type val) {
    if (arr) {
        auto buff = new Type[dsize(arr) + 1];
        for (int k = 0; k < dsize(arr); ++k)
            buff[k] = arr[k];
        buff[dsize(arr)] = val;
        delete[] arr;
        arr = buff;
        return true;
    }
    else {
        return false;
    }
}

template<class Type>
bool insert(Type*& arr, int id, Type val) {
    if (arr && dsize(arr) > id) {
        auto buff = new Type[dsize(arr) + 1];
        for (int k = 0; k < id; ++k)
            buff[k] = arr[k];
        buff[id] = val;
        for (int k = id; k < dsize(arr); k++)
            buff[k + 1] = arr[k];
        //show_arr(dsize(buff), buff);
        delete[] arr;
        arr = buff;
        return true;
    }
    else {
        return false;
    }
}

template<class Type>
void myswap(Type& a, Type& b) {
    Type t = a;
    a = b;
    b = t;
}

template<class Type>
void shuffle(Type* arr) {
    int sz = dsize(arr);
    for (int k = 0; k < 100; k++)
        myswap(arr[rand() % sz],
            arr[rand() % sz]
        );
}