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Marina Mas
6,104 PointsWhy do we need to declare the variable i ?
Why is the variable i inside the for loop declared? Why is it running in the javascript console without declaration?
1 Answer
Jonathan Grieve
Treehouse Moderator 91,253 PointsIt's what's known as a counter variable. What's happening is the loop needs a way to track how many times it should run the loop.
It's typical to have a look that has a letter for a name such as i.
for(let i=0; i< iterable_name.length; i++) {
}
So in this example, you initialise a variable with let i = 0 or another value other than 0 to start the count.
In the next part, you specify a condition for how the loop will end. It could be a hard coded value but it's more common to have the loop run for however many times as there are values in an iterable such as an array. hence iterable_name.length;
The third and final part is the incremental value which governs how many steps the loop runs until it gets to the break of the loop. i++ is a short hand for changing the value upwards by one.