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JavaScript JavaScript Foundations Arrays Methods: Part 3

Robert James
Robert James
20,491 Points

(a, b)

is anyone able to explain a little more what this (a, b); return a - b does when using fuctions!

Dont quite understand it

Thanks in advance!

2 Answers

Erick Bongo
Erick Bongo
8,539 Points

Say you had two different sums that you wanted to work out 1st sum is 5 - 3. 2nd sum is 10 - 2.

/*Here You create a function and give it two arguments.
 (a,b)  or (c,d)  or (one, two). 
These are just used to store some type of value
 later such as a = 5, b = 3 or c = 5, d = 3.*/

function subtract (a,b){

// In the actual function itself is where
// you tell the function what type of sum you 
//wish to calculate and store, so in this case 
//we tell the function we want to subtract the 
//value in b from the value that is held in a

return (a - b);

// The last part is where you would call the
// function and pass your chosen values to
// the function's arguments ()

// To work out the first sum you would write
subtract (5, 3);  

// For the second sum you would write

subtract (10,2);

//All together it would look like this

function subtract (a,b){
return (a - b);

subtract (5 - 3);
subtract (10 -2);

Note we can call the function as many times as we like placing different values in a & b to work out different values.

You have the following function:

function subtract(a,b) {
  return a - b;

This function is called subtract and takes two arguments - a and b. These two arguments are used inside the function as local variables when you perform the calculation a - b (so they only live inside the function and not before/after). This function returns a value (hence the return keyword inside the function). You could use this function to assign the return value to some other value like this:

var value = subtract(3,2);

If you used console.log(value), you would get 1.

Is this explaining what you were struggling with? Feel free to ask again if not.