14. Repeat

Often, we will find that we want to repeat a series of instructions a fixed number of times. There is a way in Javascript to do so ... but it has too many new concepts to explain at this time. I will just show you the code, and immediately introduce repeat(), a simpler replacement for it, unique to Reeborg’s World. Later, when you know more about Javascript, I will explain how repeat() is defined in terms of the standard way. The standard way is known as a for loop and is written as follows:

for (var i = 0; i < n; i++){
    // some instructions here
}

Note

Remember that take("token") could more simply be written as take().

Now that you have seen this cryptic code which includes two Javascript keywords, for and var, let’s introduce instead repeat(). We will use the example get_money() from the previous newspaper delivery example:

function get_money() {
    take("token");
    take("token");
    take("token");
    take("token");
    take("token");
}

Inside get_money(), we repeat 5 times the command take(). Using repeat(), we can rewrite the above as follows:

function get_money() {
    repeat(take, 5);
}

Note that I have not included the parentheses () for take inside repeat(). If I had to specify the argument "token", I would not have been able to use repeat as it makes use only of the name of the function, without calling it using (). Now, by using repeat() we have yet another way to eliminate repetitions in our code.

Try it!

Change your program for the newspaper problem so that you use repeat() wherever it would shorten the code. If you did not save it, go back to the previous lesson and redo it using repeat().