C++ Taskbook Level 2.7

Задание 1

Given an array of integers:

cppint arr[] = {1, 2, 3, 4, 5};

Find the sum of the squares of the elements of this array.

Задание 2

Given an array of numbers:

cppint arr[] = {1, 2, 3, 4, 5};

Merge the elements of this array into a string:

cpp"12345"

Задание 3

Given an array with a date:

cppstd::string arr[] = {"2025", "12", "31"};

From the elements of this array, collect the date in the following format:

cpp"31-12-2025"