But how do you start, what do you do, how do you tell STOS to do this.....this are the questions the beginner asks. Well in this article I'm going to waffle on about the subject of writing your own pieces of code. And show you how to write a simple game.
First......how do we start? Well....first we need to learn some commands. A program is just a group of commands that tell STOS what to do. We start off with simple commands and we type out the examples in the STOS manual. This helps to give us a good idea of commanding STOS and telling it what to do.
Lets say we wanted STOS to print something on the screen over and over again. We can use the PRINT and GOTO commands like this...
Here we have a simple program. First it prints the word STOSSER onto the screen, and then it goes onto the next line that tells STOS to go back to line 10 and print STOSSER on the screen again.10 print"STOSSER" 20 goto 10
So as you can see, we have grouped two commands together to make a small program.....actually a small program like this is better known as a routine. A program such as a game is just a large group of routines. Lets try a routine that counts up to ten.
What we have here is a loop that adds one to the varible X, prints it one the screen, then stops when X reaches 10. The HOME command is used to tell STOS to keep the counter to the same part of the screen, and the WAIT command stops STOS from printing too fast.10 for X=1 to 10 20 home:print X:wait 5 30 next X
So.....once we have learnt the commands we can easily group them together. Once you've been learning them, typing out examples, and looking at other routines, you'll find it all comes clearer.
Lets program a small game. First we have to decide what the program is going to be, and what it does. The game in question is a Guess the Number game where STOS will first choose a random number, then ask the player to guess it. If the players guess is wrong then STOS will tell him so. First....lets set up the screen.
Next we can put the games name up, known as the title screen.10 key off : hide : mode 0
Now we need to tell STOS to choose a random number, like this.20 locate 0,1 : centre"NUMBER GUESSER"
This line will choose a different number from 1 to 10 every time STOS comes across it. With programming we are sometimes faced with problems, in this case, the RND command will sometimes choose nought as a random number. The problem is that we only want numbers from 1 to 10. So therefore we add an IF THEN statement to tell STOS that if it chooses nought....then go back and try again.30 RN=rnd(10) : if RN=0 then goto 30
When STOS has chosen a number between 1 and 10, it needs to ask the player to guess the number.
Next we need a way of letting the player entering his guess.40 locate 2,4 : print"I am thinking of a number between 1 and 10" 50 locate 2,5 : print"Can you guess what it is?"
This command waits for the player to enter a number and press return. Now so far we have the RN varible which holds the random number chose by the game, and the A varible which holds the number chosen by the player. But what if the player has typed in a number which is out of range......we can check for this with these two lines.60 input A
So if the number in the A varible is out of range then the game imforms the player to try again then goes back to the input at line 60. Now we need a line to check if the player has guessed the right number........like so.70 if A<1 then print"Your guess is too low, try again" : goto 60 80 if A>10 then print"Your guess is too high, try again" : goto 60
This line checks if the A varible contains the same number as the varible chose by the game. Here we are telling the game that if the players guess is other than the number the game has chosen then to give them a chance to try again.90 if A<>RN then print"Thats not it, try again" : goto 60
Finally we need to check if the player has guessed the right number.
So there we have it. A small game produced by just a group of routines. We can easily improve it, such as getting the game to loop back to the start after the player wins. We could also add extras such as a score by simply adding points to a varible and printing it on the screen like this.100 if A=RN then print"Well done, you've guessed the number" : stop
If you are just starting on programming. Then you will be pleased to know that there is a book to help you. Its called The Beginners Guide to STOS and you can get it from MT SOFTWARE. Another good book is the Game Makers Manual also from MT SOFTWARE.110 SC=SC+10 : print"Your score is now:";SC 120 wait 50 : cls : goto 20
This is DEANO signing off...........