Example #1:
LET A=13
Output:
Nothing is displayed on the screen, but whenever A is used in the program, 13 is understood unless A changes.
Example #2:
LET A=A+1
Output:
Nothing is displayed on the screen, but A now equals 14.
One important thing to know, is that LET is hardly ever used in QBasic programs, because you can leave LET out. For example, if you write A=13, it means the same thing as LET A=13.
The variables you can use can have letters, both uppercase and lowercase, and numbers, although the name can't begin with a number. There are probably some other acceptable things that I'm forgetting here, but I'll have to check those.
Example:
LET A$="Reinier" or A$="Reinier"
Output:
Guess what!!! Nothing is displayed on the screen, but A$ is now the string containing Reinier.
Program:
10 A=13
20 B$="QBasic"
30 PRINT "Reinier is";A;"years old and he enjoys ";B$;"."
40 END
Output:
Reinier is 13 years old and he enjoys QBasic.
Line numbers are not really important, and I could've written the same program with the same output without the line numbers. I could also have some of the lines have line numbers and the rest not. The line numbers are just easy for GOTO and GOSUB, to be explained in a later lesson.
END is not really nessecary in this program. The program would end anyway because there are no commands after line 30 in this case. END serves a purpose in the middle of a program if you want to stop the program right there.
End of lesson 2.
