memory ?

I'm new to C++ so first programs naturally include a calculator.
My memory question is this:
I have a function for each math procedure(add, sub, mul, div,etc)
I have globally declared double a, b, ; for use with all the functions. I have read many places to keep the scope of variables as small as possible...So do the values of a, b, accumulate in memory by declaring them globally?.....ie :
0x00001 = a for first function
0x00002 = b for first function
0x00003 = a for second function
0x00004 = b for second function
or would they over write each other therefore using the same memory space??
A little confused by this ........appreciate any thoughts.....:^)

Don't declare variables globally. You should declare your variables a and b in the main() function. At the end of the main function, the memory set aside for a and b will be given back to the computer. Look up the reserved words auto, static, and register.

when you assign something to the variable it overwrites the previous value... You might want to try not using globals for example...

Code:

---

#include <stdio.h>

double add(double a,  double b)
{
    return a+b;
}

int main()
{
    double x = 25.367, y = 86.254;

    printf("%.3f + %.3f = %.3f\n", x, y, add(x, y));
    return 0;
}

---

joshdick & Rog
Thanks for your replys.........
I looked up those keywords and the info on static answered my question. Thanks again.....:D