Java Reference
In-Depth Information
Parameters and Arguments
Parameters and arguments are often used interchangeably to represent values that are
provided for the function to use. There is a subtle difference though: any parameters a func-
tion needs are set when the function is defined . When a function is invoked , it is provided
with arguments.
JavaScript does not have a built-in function to square numbers, so we can create one to
demonstrate using parameters. In the example that follows, the square function takes one
parameter, x , which is the number to be squared. In the body of the function, the name of the
parameter acts like a variable equal to the value that is entered when the function is invoked.
As you can see, it is multiplied by itself and the result is returned by the function:
function square(x){
return x*x;
When we invoke this function, we need to provide an argument, which is the number to be
<< 20.25
You can use as many parameters as you like when defining functions. For example, the fol-
lowing function finds the mean of any three numbers:
function mean(a,b,c){
return (a+b+c)/3;
<< undefined
mean(2, 6, 19);
<< 9
If a parameter is not provided as an argument when the function is invoked, the function
will still be invoked, but the parameter will be given a value of undefined . If we try to
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