C++ Taskbook Level 5.2

Ask the user to enter 10 numbers via the console. Fill the array with these numbers.

Given an array:

int arr[][] = {
	{1, 2, 3},
	{4, 5, 6},
	{7, 8, 9},
};

Find the sum of the elements of this array.

Given an array of integers:

int arr[] = {100, 200, 300, 400, 500};

Print to the console the elements of this array whose first digit is equal to 1 or 2.

Given an array of integers:

int arr = [123, 987, 345, 567];

Get the second element, which contains the digit 3:

345

Write a program that will output the following pyramid to the console:

1
22
333
4444
55555
666666
7777777
88888888
999999999