Pairs in C++

pair<string, int> movie = {"Frozen", 2013};   // a title and a year

cout << movie.first << endl;                  // Frozen

cout << movie.second << endl;                 // 2013

auto [title, year] = movie;                   // unpacking

cout << title << " " << year << endl;         // Frozen 2013

Full lesson:

Some values belong together. A movie has a title and a year. A point has an x and a y. C++ keeps two values like these in a pair.

• pair<string, int> is a pair of a string and an int. The types go in the angle brackets, in order.
• pair<string, int> movie = {"Frozen", 2013}; makes one. The values go in curly braces.
• movie.first is the first value, "Frozen". movie.second is the second, 2013.

auto [title, year] = movie; unpacks the pair into two new variables. You have seen this before, in for (auto& [name, points] : scores).

A function can return a pair. Its return type is the pair's type, like pair<int, int>. Then return {a, b}; builds it.

cout << movie doesn't compile. Print movie.first and movie.second instead.

Your task

Rex the dog went for a long walk. pet holds his name and his age.

First, make splitTime return its pair: the whole hours and the minutes left.

Then unpack pet into name and age.

Last, call splitTime(135). Unpack its result into hours and mins.

The code already prints the three lines.

Expected output:

Rex
Rex is 4
Rex walked 2 h 15 min