for loop as a macros
 

could somebody tell wats wrong with this
#define FOR(x,n)for(typeof(x);x<n;x++)

Re: for loop as a macros
 

Just don't use macros for loops.

Re: for loop as a macros
 

Firstly, there is no space between the closing bracket at the end of FOR(x,n) and preceding the rest. That's a stylistic concern, but badly hurts readability.

Second, and more significantly, typeof() is not a standard function or operator in C++. It is an extension specific to g++ (GNU c++) in which typeof(x) expands to be type of x and will trigger a compiler error with every compiler that does not support that extension. Within a for loop (assuming you're using g++), if x is an int, then

FOR(x,n)

would expand to

for (int; x < n; x++)

which is invalid code.

Re: for loop as a macros
 

Apart from anything else this useless macros must be

#define FOR(x,n)for(typeof(x)x=0;x<(n);x++)