Step 6 of 6

Whole lines with getline

cin >> stops at whitespace. To read an entire line, spaces included, use std::getline:

std::string line;
std::getline(std::cin, line);

It returns something that converts to false at the end of input, so this reads every line:

while (std::getline(std::cin, line)) { ... }

Your turn: read lines until the end of input and print each one prefixed with its line number, like 1: first line. Then print total N.