A function is a block of code that performs specific tasks; normally, a program contains many functions. When a function is called, the control is transferred to a different memory address. The CPU then executes the code at that memory address, and it comes back (control is transferred back) after it finishes running the code. The function contains multiple components: a function can take data as input via parameters, it has a body that contains the code it executes, it contains local variables that are used to temporarily store values, and it can output data.
The parameters, local variables, and function flow controls are all stored in an important area of the memory called the stack.
