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Functions
Declare & Define

Often, built-in functions aren’t enough to tackle the wide array of programming challenges out there. But never fear: you can write your own functions too!

A C++ function is comprised of two distinct parts:

  • Declaration: this includes the function’s name, what the return type is, and any parameters (if the function will accept input values, known as arguments).
  • Definition: also known as the body of the function, this contains the instructions for what the function is supposed to do.

This is the overall structure:

return_type function_name( any, parameters, you, have ) { // Code block here return output_if_there_is_any; }

This is what it might look like with real code:

void make_sandwich() { std::cout << "bread\n"; std::cout << "egg\n"; std::cout << "cheese\n"; std::cout << "avocado\n"; std::cout << "bread\n"; }

Instructions

Watch how the make_sandwich() function gets executed step by step!

This is just a preview of how everything works, so don’t worry about memorizing anything. In the next exercise, we’ll start building functions from scratch…

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