Question

My aim is to get two numbers and perform an corresponding to the values they hold:

For ex.. Let the vars be x and y.

I need to compute the value of another var z, as follows:

z = x + y // if x = y = 1

z = x – y // if x = 0 and y = 1

Since i need to use it several times, it would not be efficient to use if else within a loop.

What i basically require is like a macro…. preferably using #define., like if it were to be used once:

#define x + y 1 replaces x+y with 1, but does not depend on the values of x and/or y

Is there any way I could replace x+y with 1, x-y with 0 and so on…

Answer 1

If the vars are integers/any other primitive type you can’t improve the performance, since the compile will usually translate it one assembly code line. such as sub eax, ebx

Anyhow, as mentioned before, you can’t do it on compile time since x,y values are not known at compile time.

you can hint the compiler to save x and y on a register using the register keyword, which will save the variables on the CPU registers in order to preform faster calculations.