ReadLine???

Blitz3D Forums/Blitz3D Beginners Area/ReadLine???

AuzingLG

(Posted 2004) [#1]

Hello!
I've a Problem with ReadLine!

here ist my text file:

d-BATTLE
640
480
32
1

here ist the code:

path$ = CommandLine$()+"\"
gfile = ReadFile(path$+"DATA\main.cfg")

AppTitle ReadLine$(gfile)
Graphics3D Int(ReadLine(gfile)), Int(ReadLine(gfile)), Int(ReadLine(gfile)), Int(ReadLine(gfile))
WaitKey

I get the error: Illegal Graphics3D Mode

Can you help me?

skidracer

(Posted 2004) [#2]

The order that Blitz calls ReadLine for each of the 4 arguments for the Graphics3D command like other programming languages is not guaranteed (you are incorrectly assuming blitz will evaluate your 4 arguments from left to right).

You must ReadLine into variables in order to guarantee the correct order as in the following (note blitz's automatic string to int conversion):

w%=ReadLine(gfile)
h%=ReadLine(gfile)
d%=ReadLine(gfile)
m%=ReadLine(gfile)
Graphics3D w,h,d,m

AuzingLG

(Posted 2004) [#3]

thanks
it works

Rob Farley

(Posted 2004) [#4]

Also, you might want to look into using currentdir$()

JaviCervera

(Posted 2004) [#5]

The never-ending discussion. You must not assume that a compiler will evaluate the operands of a expression from left to right, but you can be sure that different expressions will be evaluated in a sequential order. The arguments of a function should be considered different expressions.

The book 'C. Reference Manual. 4th edition', by Herbert Schildt, says the following about the comma operator (translated from spanish):

When used as an operator, the comma is used to concatenate several expressions. [...] In the example 'x = (y=3, y+1);', the first element in the comma separated list must be evaluated, so '3' is assigned to 'y'. Then the result of 'y+1' is added to 'x'.