Hi Problems with figuring out while loops

[Stupidnewb]

Hi all I just started writing my first while/for/do loop and I have this assignment to calculate a user input into printing out a value. I know that seems uber vague so here is a better description:


The user inputs a value n between starting with two then I output the sum of n odd integers. So if they enter 3 then the output should be 9.

1+3+5 and what I am having trouble with is how to tell the loop when to stop. I mean I set the user input to the variable say 3 and then do I set the number of times the loop runs to another variable and then have the loop break when these two variables are equal? I am very very lost. Please help a girl out I haven't been this confused since I watched the ending of Evangelion!

[Belisarius]

You could write a PhD thesis in philosophy on Evangelion. I didn't have the patience to even try to figure it out.

This sounds like a job for a "for" loop. But if you want to do it with a while loop, that's fine too.

As I understand, you want to find the sum of 'n' odd integers.

Ok, if that's the case, you want to loop 'n' number of times. You'll need two variables, one to keep the sum and one to keep track of the loop. Here's a sample method:

public int oddSum(int n){
  int sum = 0;
  int i = 0;
  while(i < n){
    // <Enter odd-summing code here.>
    i++; // This will increase the value of 'i' by one.  It's a common programming shortcut.
  }
  return sum;
}

The loop breaks when 'i' equals 'n'. Why not when 'i' greater than 'n'? Because in programming, all things start at '0' instead of '1'. Chalk it up to tradition, but it's going to be a recurring theme in programming.

If someone wants to the sum of the first odd number, they'll enter '1'. Well, because 0 is less than 1, the loop will execute. Next time around, 'i' will equal 1, and therefore not be less than 'n', and the loop will break before executing the code again.