The void Return Type in C

In the C programming language, functions that are declared with a specific return type are expected to have a return statement, delivering a value matching that type. However, there are scenarios where a function doesn't need to return anything – perhaps it's simply displaying text on the screen. For such instances, the function should be declared with the void type.

The void keyword specifies that a function doesn't return a value, and it can also be used in the context of pointers. Attempting to declare a variable of type void will result in an error because the compiler won't understand how much memory to allocate.

Here's an intentional error for illustration.

Delving into Recursion

C supports the ability for a function to call itself, a technique known as recursion.

Imagine recursion as the action of stretching and then releasing a rubber band. It's commonly leveraged in mathematical operations, such as calculating factorials.

For instance: 3! = 3 x 2 x 1

Factorials are often utilized in approximating function values by expanding these functions into Taylor or Maclaurin series.

Note

This chapter's inspiration came right after the author completed a lab assignment at a university. The task was to approximate the cotangent value to a certain precision by expanding it into a Taylor series. And naturally, the factorial computation was indispensable.

In the context of recursion, the function will continue to call itself until it meets the condition n == 0 || n == 1. Once this condition is satisfied, the results from the subsequent factorial() function calls are returned in the reverse order, similar to folding an accordion. By the time step 6 is reached, the initial call to factorial(3) will return 6.