What does "<<" do exactly?

[Kim]

Hello,

So I did the challenge and came up with:

cout << “Welcome to Bulls and Cows, a fun word game.” <<endl;
cout << "Can you guess the “;
cout << WORLD_LENGTH;
cout << " letter isogram I’m thinking of?\n”;

This differs from the proposed solution, which is:

cout << “Welcome to Bulls and Cows, a fun word game.” <<endl;
cout << “Can you guess the " << WORLD_LENGTH;
cout << " letter isogram I’m thinking of?\n”;

My question is; Was my way less efficient? Does it really matter? And what does “<<” do exactly?

Cheers to whoever responds, Kim

[Capricas_Kirito]

The double chevrons tell the compiler that there are multiple elements subject to the command on the same line. In this case the command is “std::cout”. Technically you could have written the whole thing as:

cout << “Welcome to Bulls and Cows, a fun word game.\nCan you guess the " << WORD_LENGTH << " letter isogram I’m thinking of?\n”

(word-wrap prevents it from showing all on one line) and that would have been fine. However, ask yourself this: If you were reading an unfamiliar program, which of these three ways would be easiest to understand?

EDIT (image of the single line)

[Lucid_Stew]

<< is an operator in the iostream library. In this case, when combined with a cout object, it basically says “add this to an output stream”. Like most operators, it can be chained. Like int number = 5+5+5+5+5; or int x,y,z;

[Incantrix]

Technically, the << is called a bitwise operator which is a build in operator to C++ along with things like +, -, &&, ||…

Ostream, which is part of the library actually overloads it, which basically means customizes what it can do ( i.e. you could overload the + operator to actually subtract two numbers - good example, but in reality no one would actually do this).