Thread: Global variables, how can I add washerB to this program?

Code:

#include <stdio.h>
#include <math.h>

double	quantity1, thickness1, density1, inner1, outer1;
double product, area;
double washerA;

/*          Prototypes               */

void ReadData (void);
double FindProd (void);
double CircleArea (void);
void PrintResult (void);

int main(void)
{
	/*            Body of Control          */
	ReadData ();
	product=FindProd();
	area=CircleArea();
	washerA=product*area;
	PrintResult();
	return  0;
}

void ReadData (void)
{
	scanf ("%lf %lf %lf %lf %lf", &quantity1, &thickness1, &density1, &inner1, &outer1);
}
double FindProd (void) 
{
	double product;   /* local variable  */
	product = quantity1*thickness1*density1;
	return (product);
}
double CircleArea (void) 
{
	double area;   /* local variable  */
	area = ((3.142*(pow(outer1/2,2)))-(3.142*(pow(inner1/2,2))));
	return (area);
}
void PrintResult(void) 
{
	printf ("%0.2lf, %0.2lf\n",product,washerA);
}

Hello, I want this program to process 2 washers, in this case washerA and washerB, I must not pass any parameters in function calls.