Functions

 Functions

Functions are how we group commands together so that we can reuse them over and over in our programs.  Functions will not run their commands until called.

Function Definition:  This is how we make a new function.  When naming functions start with a capitol letter.  We start a function definition with the word “function”.  Next we put a space and then the name.  After that we put parenthesis.  The function needs a body, which we block off with the set of curly brackets.

Example:  function definition

void NameOfFunction ( )
{
commands you want the function to run when called.
}

Calling a function:  When we call a function, we are telling it to run it’s commands.  We can do this anywhere, and as many times, as we need to in our script.  To call a function we just say it’s name followed by a set of parenthesis.

Example:  of a function call

AnyFunction ( );

 Arguments/Parameters:  Arguments (or Parameters) are pieces of information a function needs to do it’s job.  We define arguments in the parenthesis after the function name in the function definition.  Arguments are variables – so you need to give them a type followed by a name.  In the example below we have two arguments that can hold integers.  This function adds the numbers together and prints the answer.

Example: a function with arguments

void AddNumbers (int number1, int number2)
{
Debug.Log(“Answer is:  ” + number1 + number2);
}

Returning a value from a function:  Sometimes we want the function to send us a value back.  To do this we use the return command.  In the example below the function will return a true or false value after applying an amount of damage to the player’s health.  If the player has more that 0 health the function will return a value of true.  Otherwise, it will return a value of false.  It returns this value through its return type which is the bool before the word function in the example below.

Example:  function returning a value

bool CheckForDeath(int damage)
{
health -= damage;
if(health >= 0)
{
return true;
}
return false;
}

Example: using a returned value from a function – in this function call we are sending 50 to CheckForDamage.  CheckForDamage will return a value of true or false which will replace the function call.  We call the function inside an if statement so we can check to see which value was returned.

if(CheckForDamage(50) == true)
{
print(“Player is alive”);
}
else
{
print(“Player is dead”);
}