Question

Can someone explain the output for this recursive function? Thank you!

function test(a) {
    while (a > 0) {
        a -= 1;
        test(a);
        console.log('after first invocation: ' + a);
    }
}

test(3);​

Output:

after first invocation: 0
after first invocation: 1
after first invocation: 0
after first invocation: 2
after first invocation: 0
after first invocation: 1
after first invocation: 0

Answer 1

Well the code does 100% what you tell him to do!

loop 1 : 
     value of a is 3, is it bigger then 0? Yes!
     3 - 1 = 2 (why not a-- ...) 
     call function test(2)
     is 2 bigger the 0? Yes!
     2 - 1 = 1 
     call function test(1)
     is 1 bigger the 0? Yes!
     1 - 1 = 0 
     call function test(0)
     is 0 bigger then 0 ? NO!
     console.log(('after first invocation: ' + 0)

I don’t think i have to do it for every output but I think you get the point?