How can a circle touch a line in Qbasic and end the program?

Question

I am trying to make a maze in Qbasic but when the pointer touches the maze lines then the program is not ending. I want that when the circle (which is the pointer ) touches the ends of the maze then the program should go to an end.The Program is this:- ``` cls screen 12 DIM p AS STRING DIM A1 AS STRING 15 print"What do you want to do?" print"A:Draw AN IMAGE"," B:PLAY A MAZE GAME"; PRINT PRINT"TYPE 'A' OR 'B'IN CAPITAL FORM" GOTO 102 99 print "rules to play the maze game:" print print "1 use 'W' to move the ball foward" print "2 use 'S' to move the ball backward" print "3 use 'A' to move the ball leftward" print "4 use 'D' to move the ball rightward" INPUT A1 CLS goto 10 102 INPUT P if p="A"then cls goto 20 elseif p="B" then cls goto 99 elseif p<>"A" AND p<>"B" then print "Choose between A and B" GOTO 70 end if 10 pset(120,120) draw "r100" pset (120,140) draw"r80" pset (200,140) draw "d100" pset (220,120) draw"d140" pset (220,260) draw "l90" pset (200,240) draw "l50" pset (130,260) dra…

Accepted Answer

Ok, let's take a peak at your game loop presented below and reformated a bit for readability:

```
do
    k = ucase$(inkey$)

if k="W"then
        y = y - 2
    elseif k= "S" then
        y = y + 8
    elseif k="A"then
        x = x - 8
    elseif k="D" then
        x = x + 5
    end if

circle (x,y),7,10
loop until k ="Q"
```

Your win case (if x=120 and y=120 then goto 45) doesn't actually occur within the loop but outside it.

With do loops, only the code between the do and loop statement will execute unless the "until" statement returns true. In order words:

```
do
    'This code will execute 
loop until k = "Q"
    'This code will only execute after k=Q
```

Put the win case in the do loop and it should work.

If I recall correctly, QBasic allows whitespace in the beginning of a line. I recommend using whitespace to organize your code visually so you can see what's going on. Look at how I formatted your main loop. Everything that the do loop controls is tabbed to the right of the do and loop statement. This way you can easily see what the do loop is doing. Everything in the if statement gets the same treatment for similar reasons.

If you get in the habit of indenting your code, you can start to see the code's logic laid out cleanly.

Edit: It seems you're new to programming. If you enjoy it, I recommend learning Python through codecademy rather than QBasic. QBasic encourages some very bad habits, like goto statements.

How can a circle touch a line in Qbasic and end the program?

Solution

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