need help explaining proper use of pointers

[dgilroy1210]

I need an explanation of correct use of pointers within functions.

say i had a structure like this:

#include <stdio.h>
#include "my.h"


int main(void)
{
int length, width, customerdiscount, area;
double costpersquarefoot, carpetcharge, laborcharge, installedpricecharge, discountcharge, subtotalcharge, taxcharge, totalcharge;

read_data(&length, &width, &customerdiscount, &costpersquarefoot);

calculate_values(length, width, customerdiscount, costpersquarefoot, &area,
                          &carpetcharge, &laborcharge, &installedpricecharge,
                          &discountcharge, &subtotalcharge, &taxcharge, &totalcharge);

printresults(length, width, area, carpetcharge, laborcharge, installedpricecharge,
                    discountcharge, subtotalcharge, taxcharge,   totalcharge, costpersquarefoot);


return 0;
}

when I call these functions. the first calls no other functions, the second calls 3, and the print calls 2... if they are going to change in the function i use *variablename, if not then its variablename? also when a function looks like this:

void calculate_total (double* variable1, double* variable2, double variable3, double variable4,)
{
variable1 = variable3 * variable4;
variable2 = variable3 + variable4;
return;
}
how do i refer to it when i bring it back into main to use with all of the other functions?

[quzah]

So what's your actual question? Pointers in C - Tutorial - Cprogramming.com


Quzah.

[AndrewHunter]

And for a more detailed description: Prelude's Pointer Tutorial