WEBVTT

1
00:00:00.117 --> 00:00:02.003
In this demo I'm going to enter some 

2
00:00:02.004 --> 00:00:03.220
statements in the CodePad

3
00:00:03.228 --> 00:00:06.110
and the first statement I enter will simply declare

4
00:00:06.111 --> 00:00:08.001
and assign a value to a variable 

5
00:00:08.003 --> 00:00:10.118
that I'm going to use in the other statements.

6
00:00:11.002 --> 00:00:13.113
I'll declare and Integer variable X

7
00:00:13.114 --> 00:00:15.221
and assign that a value of zero

8
00:00:15.226 --> 00:00:18.222
and end the statement with a semi-colon.

9
00:00:20.221 --> 00:00:23.007
Now I'm going to enter a statement that changes the value

10
00:00:23.008 --> 00:00:27.222
of that variable X, I'm going to assign a new value to X

11
00:00:28.003 --> 00:00:30.001
so I need the assignment operator

12
00:00:30.113 --> 00:00:33.008
and what I'm going to assign to it is an expression

13
00:00:33.116 --> 00:00:36.117
that contains the current value of X

14
00:00:37.004 --> 00:00:39.116
and adds ten onto its value,

15
00:00:40.007 --> 00:00:44.004
and again I end the statement with a semi-colon

16
00:00:45.115 --> 00:00:47.005
and nothing obviously happens there

17
00:00:47.110 --> 00:00:49.003
to see the effect of that statement

18
00:00:49.007 --> 00:00:51.007
I have to type the name of the variable

19
00:00:51.113 --> 00:00:54.009
as an expression without the semi-colon

20
00:00:54.223 --> 00:00:57.112
and press enter, and I see that 

21
00:00:57.113 --> 00:01:00.223
the value has changed from zero to ten.

22
00:01:02.002 --> 00:01:05.119
Next I'm going to try a statement with a decrement operator

23
00:01:05.226 --> 00:01:09.113
so X and the decrement operator

24
00:01:10.113 --> 00:01:14.001
and again end the statement with a semi-colon

25
00:01:14.228 --> 00:01:18.003
and again nothing obvious happens because its a statement

26
00:01:18.113 --> 00:01:21.115
and I need to enter the value of the variable to see

27
00:01:21.116 --> 00:01:23.225
the effect thats had, and that has decremented

28
00:01:23.226 --> 00:01:25.115
the value of X.

29
00:01:27.008 --> 00:01:29.118
Finally I'm going to write a statement to declare

30
00:01:29.119 --> 00:01:31.229
and initialise another variable Y

31
00:01:32.110 --> 00:01:35.009
if I tried to use that variable before I declare it

32
00:01:35.119 --> 00:01:38.004
I get an error so lets declare

33
00:01:38.009 --> 00:01:40.006
this is going to be a double

34
00:01:41.002 --> 00:01:43.119
and I'll give it some value

35
00:01:46.007 --> 00:01:49.221
and execute the statement, now I should be able to see

36
00:01:49.226 --> 00:01:52.226
just by typing the name of the variable that

37
00:01:53.001 --> 00:01:55.007
the variable exists because its been declared

38
00:01:55.111 --> 00:01:57.229
and it has the value I assigned to it.