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JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops Review For Loops and Loop Exiting

Posted by Jennifer Rén
Jennifer Rén
5,752 Points

Why does this run 11 not 10 times ? for (var j = 0; j<=100; j += 10;); console.log(j);

To my mind the logic is the var is 0, its checked as less than 100 so 10 is added. the first log would be 10 not 0?

2 Answers

KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,970 Points

You code won't run with the semicolons but I get what you are asking. j += 10 adds 10 each time after the code in the for loop executes. So the initial value of 0 will be logged then 10 will be added.

Jennifer Rén
Jennifer Rén
5,752 Points

So basically it does log the 0 before it runs the + 10. I seeeeeee. Thanks!

Linas Mackonis
Linas Mackonis
7,071 Points
Linas Mackonis
Linas Mackonis
7,071 Points

Jennifer, first loop starts from 0. Since you wrote j <= 100, it will run 11 times, because it will run until it will be equal to 100. If you want it to run 10 times, remove '=' sign. Also, remove ';' from the last argument 'j += 10;' .

It should look like this: 

for (var j = 0; j<100; j += 10) {
 console.log(j); 
}