README.md

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This tutorial intends to teach beginners how to use functions in programs along with the various terms used like 'calling' a function and 'passing' values to a function and so on.

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By	Karthik A
Level	Beginner
User Rating	5.0 (15 globes from 3 users)
Compatibility	C, C++ (general)
Category	Documents
World	C / C++
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Introducing C++ - Part 3

 

Functions

 

        We will now see the usage of functions is C++. Functions are very useful if you desire to use a particular set of statements or a particular operation again and again. With the help of a simple example i will explain the concept of functions.

The general form of a function is

     return-type function-name (parameter 1, parameter 2)

     {

 

     }

        return-type     -> Its the value that the function will return after various calculations.

        function-name -> This is the name of the function that we like to use

        parameter 1    ->  This is also called as the argument. These are the variables that are being passed on to the function

        parameter 2    ->  Another variable that is passed to the function

        I will illustrate the use of functions with the help of the following example

#include<iostream.h>

int add(int x, int y)

{

int z;

z=x+y;

return z;

}

void main()

{

int a=3,b=5,c;

c=add(a,b);

cout<<"The sum is "<<c;

}

 

Let us see how the code works

int add(int x, int y)

{

int z;

z=x+y;

return z;

}

        In the above code segment 'add' is the function name and 'int' is the return-type.

       There are two parameters 'int x' and 'int y'.

       The variable int z is used to store the sum of the two numbers.

        As mentioned before,

              return z;

         the integer z is returned back.

 

            Ok but where does the terms 'calling' and 'returning' the values arises? We will see that...

        In the main section you will be able to the lines

int a=3,b=5,c;

        Here we are declaring (and initializing) a and b and declaring a variable c.

        Consider the following line:

c=add(a,b);

        At this point the function gets 'CALLED'. The function 'add' is called with two parameters 'a' and 'b'. It is said that the integers a and b are passed to the function 'add'.

        When the function is called the program control is transferred to the 'add' function. The two parameters a and b are added and 'RETURNED' through the variable 'z'. This variable is stored in 'c' and then printed.

        This is how functions work in C++ and any other language. This is just one way of using functions and you will know more as you proceed.

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