What are the internationalizes, conditions, and instants that I need to fill out?

But, How would you think "What do I put in this for in loop?" so, I don't get confused later on into the future.

To decide whether to use a for loop, you should understand first if there is a set number of loops required. So, if you're iterating through an array, a forloop is perfect. If you're waiting for a user to input a specific word, a for loop isn't for you! Use a while loop, or something similar.

There are two constructs of a for loop. The first, the long-hand mthod, is what you initially asked about. It takes a counter, a condition upon that counter to stop the loop, and something that changes the counter so we don't run forever. In Objective C it would look something like:

   int a;
   for( a = 0; a < 20; a = a + 1 )
   {
      NSLog(@"value of a: %d\n", a);
   }

(You may be able to declare the int inside the loop like this: for(int a = 0, a < 20, a = a + 1). You can also manage the increment more easily by using a++ rather than the long-winded a = a + 1)

The short-hand version, removes the need for the condition and the increment. The example above is using integers to demonstate the loop, this isn't ideal as to show the shorthand version, the for in loop, needs a range of numbers which may confuse you. Take [@0 to:@19] - this is a range of numbers from zero to nineteen - just like in the example above. Rather than coding the counter to start at zero and stop at not-less-than-twenty, we can use a range of 0 to 19 just the same. (There is one difference that we can cover later!). So, the for in loop would take this range and rather than us having to tell the loop where to start and end, it just does it for us. We do need something to hold each iteration, though, so a variable of the appropriate data type is still required:

for(NSNumber *num in [@0 to:@19]){
  // do something with num
}

So, if you have a collection of objects; arrays, dictionaries, JSON files, sets or other such things - iterating through these is best done with a for loop. Using the short-hand syntax is easier than the longhand, but you can do it the long way if you want. Let's say your array NSArray *array; has a method called count that returns the number of elements in the array - it does, I think. You could than do something like:

NSArray *array = [// create an array in here];
int i; // maybe do this inside the loop
for(i = 0; i < array.count; i++){
  // do something in here:
  Log(@"%@", array[i]);
}

That was a rubbish example; sorry!

The one difference that long-hand can make is the ability to alter the route of execution. This is really bad practice so don't do it, but rather than just incrementing i you can mess with its value if you want. Say, you want to start looping again if one of the array elements contained "Steve". There's no reason why you would want to do this - but go with it for a moment ...

NSArray *array = [// create an array in here];
int i; // maybe do this inside the loop
for(i = 0; i < array.count; i++){
  // do something in here:
  Log(@"%@", array[i]);
    if(array[i] == @"Steve"){
      i = 0;        // starts the loop again! 
    }
}

Here, we've messed with the value of i and set it to zero. This will restart the loop. We could have set it to anything! Worse, we could have set i to greater than array.count` which would cause all sorts of problems! So, don't mess with your loop counter - it's a good rule but I thought I'd show you to demonstrate the point.

Anything else I can cover for you?

Steve.

P.S. My Objective-C is very rusty so please accept my apologies for any bad code syntax!