Function and Recursion

Basically in this session, we are taking about how we separate a program into different modules.
The main module is the one which we usually make as "int main" in C / C++, and there are many which are called "functions".

1. Function

In short programs, this would pretty much be useless. But, in long term and big-shot programs like applications, games, etc., this is so useful. A name of a function represents all of its "functions" which is already made in the initialization before we call the main module / int main.

Example:

int strlen(char s[100]){
     int i = 0;
     while(s[i]!=NULL){
          i++;
     }
     return i;    //this means the result value which will be returned after it is run by the function is i.
}


2. Recursion

Ever heard of loop and repetition right? This is just an implementation of loopings and repetitions inside a function, calling the function itself again and again until it fulfills some certain condition.