stupid C++

[jsun9]

newbie here to C++

can someone tell my this would fail??

p1=p1+4
p2=p1-1

for ( source = 17; source != p2; source--)

it works if i said

for ( source = 17; source != 3; source--)

[Kasracer]

is p1 initialized?

[jsun9]

i believe

int	p1,p2;

[PT Exorcist]

Originally posted by jsun9
i believe

int	p1,p2;

You declared the variables, but there is NOTHING inside.

p1=p1+4

How are you excepting that : p1 = nothing + 4 will ever work?

[jsun9]

wha? how am I supposed to increment p1 by 4?

[PT Exorcist]

Originally posted by jsun9
wha? how am I supposed to increment p1 by 4?

What you have to understand is that int p1 is ONLY a int and contains NOTHING inside because you still didnt set it to anything..so if it is NOTHING you can't increment it. Simply put you must do int p1=0; or whatever..

I think this is quite obvious..

[jsun9]

thanks.......

[Comreak]

For future reference, only global variables (variables declared outside a function, including the main() function) are automatically initialized. Everything else is filled with whatever ramdom junk is in memory (including values of previous variables).

[CornedBee]

Not even global variables are initialized. There is no automatic initialization for primitives anywhere in C++.

[Comreak]

Originally posted by CornedBee
Not even global variables are initialized. There is no automatic initialization for primitives anywhere in C++.

You sure about that?

http://cplus.about.com/library/weekly/aa101902k.htm

Global integers(for example) are consistently initialized to zero in both GCC and MVC++.NET.

[CornedBee]

Ok, you're right. They are initialized.

[PT Exorcist]

Why global vars are initialized and the others are not?

[CornedBee]

Because the C++ standard says so?

I guess it's a speed issue. Local variables would have to be initialized every time the function is called, global vars get initialized once by the exe loader.

[visualAd]

Originally posted by PT Exorcist
You declared the variables, but there is NOTHING inside.


How are you excepting that : p1 = nothing + 4 will ever work?

Well actually they contain whatever was in those 4 particular bytes of memory occupied by the integer last. Junk basically, stuff like:
-839295