Working With Integers
(Continue)
Answer:
5
2 +
3
5
2
3
6
Why is that?
Lets pass over the code line after line:
Dim Blah
As Integer
A new
Integer with the name Blah has been declared
Blah = 2
Now Blah holds the
value 2
Print 2 +
3
When you execute
command (the Print command in the case)
on expression, Visual Basic will
evaluate the expression first,
and then will execute the command on the
evaluation result.
In this case we execute the command Print on the
expression 2 + 3.
The expression will be evaluated: 2 + 3 = 5.
The
evaluation result is 5, and then Visual Basic will
execute the command
Print 5
So in other words, Print 2 + 3 is equivalent to Print 5
after executing the Command Print 5
, 5 is been printed on the form.
Print "2 + 3"
As I said before,
Everything that found inside quotes is being
treated as a string. So the
string 2 + 3 will be printed on the
form.
Print 2 + 3 will print
the value of the expression 2 + 3,
Print "2 + 3" will print the text string 2 + 3
Print Blah +
3
Now the expression is Blah + 3.
when a variable
is found inside expression, it's being
replaced with its value.
In this
case the value of the variable Blah is 2.
So the Blah in the expression is
being replaced with 2.
After the replacement the new command is Print 2 +
3
As we saw earlier, after executing this
command
the value 5 will be printed on the form.
Print Blah
Will replace the Blah with its value.
Because the Blah
value is 2, After the replacement
the new command will be Print
2
After executing this command, the value 2
will be printed on the
form.
Blah = Blah + 1
The line above
simply says:
Put in the Blah variable, the value of the expression Blah +
1
The computer is first evaluate the expression Blah + 1
Blah is being
replaced with its value: 2.
After the replacement the computer evaluates the
expression 2 + 1.
The expression value is 3.
So now, after the "Blah + 1"
expression evaluation,
the command is: Blah = 3
As you know by
now, this command will
put the value 3 in the Blah
variable.
Summary:
After executing the command Blah = Blah +
1,
the value 3 will be inserted into the Blah variable.
Print
Blah
Will replace the Blah variable with its value:
3.
So the command that will be eventually executed is Print
3
Blah = Blah + Blah
Will Put in
the Blah variable, the value of the expression Blah + Blah
The computer is
first evaluate the expression Blah + Blah
Blah is being replaced with its
value: 3.
After the replacement the computer evaluates the expression 3 +
3.
The expression value is 6.
So now, after the "Blah + Blah" expression
evaluation,
the command is: Blah = 6
After executing the command
Blah = 6,
the value 6 is being inserted into the Blah variable.
Print Blah
Will replace the Blah variable with its value:
6.
So the command that will be eventually executed is Print
6