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In this JavaScript lesson on Codecademy it is required to write a do/while loop, I have written this, and it passes

var getToDaChoppa = function(b){
  var a = b;
  do{
    console.log("Dunno!");
    } while (a < b);

};

getToDaChoppa(25);

But when looking closely at my code, I think that I may have done it completely wrong since a has no defined value?

Or since the variable of b is local inside the function, it does not affect the b argument which is passed a value of 25?

Many thanks in advance.

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4
  • 3
    Yes it is wrong since nothing modifies either a or b Commented Aug 27, 2013 at 14:51
  • Since a = b and neither is modified later, a < b will always be false. The body of your loop will only run once. Commented Aug 27, 2013 at 14:52
  • Which is why it passes since they wanted you to pass the loop only once Commented Aug 27, 2013 at 14:53
  • 1
    the code can be wrong or not depending on what you expect from it, it compiles, that's an start Commented Aug 27, 2013 at 14:58

6 Answers 6

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4

It simply does only one iteration, because when the do while loop starts, the condition is not satisfied because a and b are equals. So 

var getToDaChoppa = function(b){
  var a = b;
  do{
    console.log("Dunno!");
    } while (a < b); //25 < 25, exit 

};

getToDaChoppa(25);

If you want to try a do while loop try with some trick like 

var getToDaChoppa = function(b){
  var a = 10; //or whatever minor than b 
  do{
    console.log("Dunno!");
    a++; //when it reaches 25 or whatever value you set it breaks the loop
    } while (a < b);

};

This is just an example to let you figure out how do while works

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Comments

3

The code's fine, the logic's wrong. You are assigning a the value of b, so they'll be always equal.

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Comments

1

You are assigning the value of b to a with the statement var a = b;

The loop will run once since you are using a do while loop.

The code is not wrong, it is designed to illustrate that the condition is evaluated after the first iteration of the loop.

http://jsfiddle.net/puleos/QXC9z/

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Comments

0

Is this JavaScript code wrong?

depends on what problem you wanted to solve.

It looks pretty useless to me since the body of the loop will always be executed once.

while (a < b);will always return false because of var a = b; and a is not modified in the loop.

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2 Comments

a < b will always be false, not true
yes... my brain was twisted because of the awesome method-name
0

I think what you're after is:

var getToDaChoppa = function(b){
  var a = 0;
  do{
    console.log("Dunno!");
    a++;
  } while (a < b);

};

As mentioned by other posters, if a = b the loop will only run once. This version should run the expected number of times (if that truly is what's expected).

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Comments

0

Since the question says "Your loop should print a string of your choice to the editor one time", I think this is correct. Your code will print the string "Dunno!" exactly one time.

However the a and b variables and the do..while loop might as well not exist at all, they are only adding unnecessary complexity to the code which could be simplified to one line (the console.log() call).

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