C++ Taskbook Level 5.7

Задание 1

Print to the console all numbers in the range from 10 to 1000, the sum of the first and second digits of which is equal to five.

Задание 2

Given an array:

cpp{
  {1, 2, 3},
  {4, 5, 6},
  {7, 8, 9},
}

Merge the elements of this array into one one-dimensional array:

cpp{1, 2, 3, 4, 5, 6, 7, 8, 9}

Задание 3

Two lines are given:

cppstd::string str1 = "12345";
std::string str2 = "45678";

Get characters that are in both lines:

cpp"45"