Computer Science Canada

Need help with Changing variables
Author:  supersaiyan1 [ Thu Nov 30, 2006 8:24 pm ]
Post subject:  Need help with Changing variables
code:
var score : real
for test_num : 1 .. 5
    put "Enter the score for Test ",  test_num, "."
    loop
        get score
        exit when score >= 0 and score <= 100
        put "The mark is out of range..."
        put "Please enter a valid mark."
    end loop
    put "Your mark for Test ", test_num, " is ", score / 100 : 4 : 1
end for


k my program
when i enter letter instead of number, it crashes
is there a way to make it stop crashing
if yes can u plz explain me

Code tags added by your friendly neighborhood spiderm... err... mod.
Author:  uberwalla [ Thu Nov 30, 2006 8:50 pm ]
Post subject: 
ok i cant really think of it right now but im pretty sure its possible, ima go watch t.v and ill try to think about it a bit. and by the way when u put ur code in ur post plz make use of the code tags and indenting ur code in turing so that it is easier to read.
Author:  [Gandalf] [ Thu Nov 30, 2006 9:07 pm ]
Post subject: 
Welcome to compsci.ca!

The solution to your problem lies in error proofing, which was covered in Cervantes' String Manipulation Tutorial. In essence, you will read in the integer as a string, and then convert that string back to an integer if it doesn't contain any non-numerical characters. Read through it, and you should be able to accomplish what you seek.

And yes, next time make sure to put your code inside [ code ] [ /code ] tags (without the spaces).
Author:  sweetiechic [ Sat Dec 02, 2006 12:49 am ]
Post subject: 
k well this is the way I learned how to bulletproof my work:

code:
procedure getscore(var number: int)
var input: string
   loop
      get input
      exit when strintok (input)
      put "Not a possible score. Please enter a test score:"..
   end loop
number:= strint(input)
end getscore


and then when u want to get a score use 'getscore' instead of 'get'
Author:  Clayton [ Sat Dec 02, 2006 2:04 am ]
Post subject: 
that is in essene correct, perhaps you should put that into a function, generally, whenever you can use a function over a procedure, do it.
Author:  sweetiechic [ Sat Dec 02, 2006 8:43 pm ]
Post subject: 
ohh ok, I thought you couldn't output anything in a function though..? and there's a put statement in the procedure
Author:  Silent Avenger [ Sat Dec 02, 2006 9:37 pm ]
Post subject: 
Functions do have outputs, otherwise they wouldn't be of much use.
Author:  [Gandalf] [ Sun Dec 03, 2006 12:42 am ]
Post subject: 
Silent Avenger wrote:
Functions do have outputs, otherwise they wouldn't be of much use.

This statement is no doubt confusing.

While it is possible to output something in a function, the main point of a function is to return a value. So instead of having:
code:
proc timesTwo (n : int)
    put n, " times two is: ", n * 2
end timesTwo
timesTwo(5)

You would have:
code:
fcn timesTwo (n : int) : int
    result n * 2
end timesTwo
put "5 times two is: ", timesTwo(5)

:


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