WEBVTT

0
00:00.680 --> 00:06.800
Now so far what we have seen are all operators that exist in normal mathematics.

1
00:07.020 --> 00:10.970
But here are some that only exist in programming.

2
00:11.310 --> 00:14.050
So take a look at this expression.

3
00:14.070 --> 00:17.590
We create a variable called x and we set it equal to 5.

4
00:17.700 --> 00:23.760
Then we change the value of x to the previous value, 
which is 5, plus 1.

5
00:23.880 --> 00:26.070
So x now equals 6.

6
00:26.070 --> 00:29.790
Now we've seen this and we've been using this in our previous code.

7
00:29.850 --> 00:31.870
So this should be familiar to you already.

8
00:31.920 --> 00:39.360
But in most programming languages, instead of writing out x = x + 1, you can simply write 

9
00:39.420 --> 00:49.260
x++, and, in exactly the same way, x now gets incremented by 1 and is now equal to 6. So x++

10
00:49.650 --> 00:56.760
is the equivalent of saying x = x + 1, and this is called the increment expression.

11
00:56.760 --> 00:58.740
Now you can go the other way as well.

12
00:58.740 --> 01:00.950
You can write x--,

13
01:01.080 --> 01:05.250
and this is equivalent to x = x - 1.

14
01:05.280 --> 01:10.650
So the previous value of x, 5, minus 1, so x now equals 4.

15
01:10.920 --> 01:13.440
And this is called the decrement expression.

16
01:13.440 --> 01:20.670
Now you might have heard of the programming language C and C++, and this is kind of like a programmer's

17
01:20.670 --> 01:24.720
idea of a good joke, even though nobody else thinks it's funny.

18
01:24.750 --> 01:31.100
But essentially C++ was meant to be an increment on the C programming language.

19
01:31.110 --> 01:37.920
So it's kind of like C plus one, a little bit better than C.  Remember that with ++ and --,

20
01:38.040 --> 01:40.890
you're only ever changing the value by one.

21
01:40.890 --> 01:47.790
Now if you ever want to increase the value of x by more than one, then you can use the +=, and

22
01:47.800 --> 01:52.280
this is equivalent to saying x = x + 2.

23
01:52.350 --> 01:55.400
And so x now equals 7. In the same way,

24
01:55.410 --> 02:00.530
you can also use += to increase by the value of another variable.

25
02:00.540 --> 02:05.370
So in this case x = x + y, which is equal to 8.

26
02:05.370 --> 02:10.270
And this also works with -=, *=, /=,

27
02:10.410 --> 02:13.850
and it's a handy shorter way of doing exactly that.

28
02:13.860 --> 02:15.660
So, in the next lesson,

29
02:15.690 --> 02:19.620
I have a brief quiz for you to see if all of this stuck

30
02:19.740 --> 02:21.390
and if it makes sense.

31
02:21.480 --> 02:27.300
So head over there and see if you can complete the multiple choice question and I'll see you on the

32
02:27.300 --> 02:28.190
next module.