- While Loops 3:55
- For Loops 3:15
- For Loops 1 objective
- Foreach Loops 4:04
- Foreach Loops 1 objective
- Magic Numbers and Constants 3:13
- Constants 1 objective
- Putting It All Together 5:13
- Commenting 1:50
- Commenting Code 3 questions
- Playing the Game 4:59
- Static Members 4:39
- Static Members 1 objective
- Using Static Fields 3:40
- Wrap Up 2:30
- Wrap-up 2 questions
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For Loops
3:15Some while loops can be written more succinctly as for loops.
This pattern of using an integer that
increases each time the loop runs, is so
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common that there's a special
kind of loop just for that.
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It's called a for loop.
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I'll write what that looks like lower
existing loops so we can compare the two.
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This is doing
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exactly the same
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thing the while loop, up here does.
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We can break our while loop
up here into for parts.
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First, we declare index as an integer and
initialize it to 0.
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Second, we check to see if we’ve looped
through all the indexes of the array.
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Third, we do something with each of the
array items Fourth, we increment index so
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that the next time through the loop we're
getting the next item in the array.
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For loops also have the same for
parts only there written more concisely.
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Here's where we declare index as
an integer and initialize it to zero.
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Here's where we check to see if we've loop
through all the indexes of the array.
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The body of the loop is used for
doing something with the array item.
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And here's where we increment index so
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that the next time through the loop we're
getting the next item in the array.
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Just think of for loops
as condensed while loops.
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Now that we have this for loop we
don't need this while loop anymore.
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For loops aren't only used for
looping through a race.
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They're also really handy when we want
to count from one number to another.
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We can set the starting number here and
it can be any number we want.
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We decide where to stop counting here.
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This can be any condition that eventually
stops the loop by evaluating to false.
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Each time the loop runs,
index will count up by one.
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In fact, this variable is
often called a loop counter.
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We could also count by more than
one by using plus equals like this.
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This will count up by two.
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We want to count by one so
I'll change this back to index plus plus.
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Because this variable index
is being declared right here,
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its scope is limited
to inside of the loop.
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That means that it can only
be used inside the 4 loop.
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If we want to access the loop counter
variable after the 4 loop has ended,
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we'd have to move the declaration
up here above the 4 loop somewhere.
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[PAUSE] It may look strange, but
this is perfectly valid code.
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When reading code, you'll notice that
most for loops use the single letter I
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as the name of the loop counter variable.
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This tradition goes all the way back to
the first programming languages created.
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You can name it whatever makes sense for
your code though.
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Just to maintain tradition I'll
shorten index to I for us.
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