pointer problem


 
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# 1  
Old 01-19-2012
pointer problem

Does anyone know?
Code:
int x = 1;
int *p = &++x;       //ok !
int *q = &x++;      //gives an error :O

why the first pointer is ok but the second is an error?
# 2  
Old 01-19-2012
They're both wrong. You can't take the address of an expression, only an lvalue -- a variable.

Your compiler shouldn't be letting you do the first one if it is. Its result may be undefined.
# 3  
Old 01-19-2012
the first one does work. but the second one doesn't.
# 4  
Old 01-19-2012
Certainly not here, and I can understand why the compiler wouldn't let me take the address of an expression -- they don't really have one.

Just because something compiles doesn't make it meaningful, anyway.

What's your compiler?
# 5  
Old 01-19-2012
mine is GCC (the GNU compiler)
# 6  
Old 01-19-2012
Mine is also gcc.
# 7  
Old 01-19-2012
wierddddd :O
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