Why is this do/while loop crashing?

Question

var doLoop = ("This is a do loop ya'll");    
var doLoopArray = [];    
var doLoopCount = 1; 

do (console.log(doLoop)); 
while(doLoopCount <= doLoop.length); {
     console.log(doLoop(0, doLoopCount));
     doLoopCount += 1;
}

I thought this do loop would run 23 times (number of characters in the doLoop string and then stop, but it seems to be infinite.

Answer 1

The problem is that you have the code body after the while . That's not where it goes with a [ do-while 2 ! The code is supposed to go in the do block.

Your code is being parsed as:

do{
    (console.log(doLoop));
}
while(doLoopCount <= doLoop.length);
{
     console.log(doLoop(0, doLoopCount));
     doLoopCount += 1;
}

This is why it is an infinite loop. It sees the code in the {} as a block , and not part of the do-while structure.

You need to structure the do-while correctly. It should probably be:

do{
    console.log(doLoop);
    console.log(doLoop(0, doLoopCount));
    doLoopCount += 1;
} while(doLoopCount <= doLoop.length);

PS doLoop(0, doLoopCount) is not going to work. doLoop is a string, not a function.

Answer 2

do syntax is:

1. do
2. statement or block
3. while condition

You have your while condition immediately following the do and then you have the block.

It should be:

do {
    console.log(doLoop); 
    // You also need to fix this line. `doLoop` is a string, so you can't call it
    // as a function, but I'm not sure what you are trying to do here.
    console.log(doLoop(0, doLoopCount));
    doLoopCount += 1;
} while(doLoopCount <= doLoop.length);

Answer 3

Here is your code, with intuitive indenting.

var doLoop = ("This is a do loop ya'll");    
var doLoopArray = [];    
var doLoopCount = 1; 

do ({
  // You never increment doLoopCount in the body of the loop
  console.log(doLoop);
} while(doLoopCount <= doLoop.length);

// This is a separate block that is not part of the loop.
{
  // doLoop is not a function.
  console.log(doLoop(0, doLoopCount));
  doLoopCount += 1;
}

Your loop will run infinitely, and never reach the illegal call at the end.

What you probably meant was something like

var doLoopCount = 1; 
console.log(doLoop);
while (doLoopCount < doLoop.length) {
  console.log(doLoop[doLoopCount]);
  doLoopCount += 1;
}

or better yet

console.log(doLoop);
for (var doLoopCount = 0; doLoopCount < doLoop.length; ++doLoopCount) {
  console.log(doLoop[doLoopCount]);
}