#include <iostream>
using namespace std;

int main(){
    int twoDArray[3][2];    // 3 rows 2 columns
    twoDArray[0][0] = 11;
    twoDArray[0][1] = 22;
    twoDArray[1][0] = 33;
    twoDArray[1][1] = 44;
    twoDArray[2][0] = 55;
    twoDArray[2][1] = 66;

    cout << "-- 2d array using rows and columns --" << endl;
    for(int row = 0; row < 3; row++){
        for(int col = 0; col < 2; col++){
            cout << "twoDArray[" << row << "][" << col << "]:" << twoDArray[row][col] << endl;
        }
    }

    cout << endl;
    cout << "-- 2d array using pointer --" << endl;
    int *ptr = &twoDArray[0][0];
    for(int i = 0; i < 6; i++){
        cout << "twoDArray[" << i << "]:" << *ptr << endl;
        ptr++;
    }

    cout << endl;
    cout << "-- using dynamic array --" << endl;
    int arraySize = 4;
    int *newArray = new int[arraySize]; // attempt to allocate memory
    if(newArray != nullptr){    // successful memory allocation
        for(int i = 0; i < arraySize; i++){
            newArray[i] = i;
        }
    } else {
        arraySize = 0;  // fail to allocate
    }

    for(int i = 0; i < arraySize; i++){
        cout << "newArray[" << i << "]: " << newArray[i] << endl;
    }

    delete[] newArray;  // return memory
    newArray = nullptr; // set to null to be safe

    return 0;
}