/* This program calculates the Ohms's Law
   OHMS.CPP
   Name : Yidong, Shin
   Student Number : 011-655-057
   Program : PRG155
*/

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>

main ()

{
float V, I, R;
int choice;     // this variable used for choice
char reply;     

/*** Input Stage ***/
clrscr();
printf ("This program calculates V or I or R using Ohm's Law.\n");
printf ("\nChoose a number to calculate:");
printf ("\n1. Voltage");
printf ("\n2. Current");
printf ("\n3. Resistance");
printf ("\n0. Exit");
printf ("\n > ");
scanf("%d", &choice);

/*** Processing Stage for 1 ***/
if (choice==1)

{
printf ("\nEnter current > ");
scanf("%f", &I);
printf ("\nEnter resistance > ");
scanf("%f", &R);
V = I * R;

/*** Output Stage for 1 ***/
printf ("\nThe volatge is %.2f volts\n", V);
printf ("\ndo you want to quit (y/n) > ");
fflush(stdin);
scanf ("%c", &reply);

if (reply == 'y' || reply == 'Y')
exit(0);
}

/*** Processing Stage for 2 ***/
else if (choice==2)

{
printf ("\nEnter voltage > ");
scanf("%f", &V);
printf ("\nEnter resistance > ");
scanf("%f", &R);
I = V / R;

/*** Output Stage for 2 ***/
printf ("\nThe current is %.2f amps\n", I);
printf ("\ndo you want to quit (y/n) > ");
fflush(stdin);
scanf ("%c", &reply);

if (reply == 'y' || reply == 'y')
exit(0);
}

/*** Processing Stage for 3 ***/
else if (choice==3)

{
printf ("\nEnter voltage > ");
scanf("%f", &V);
printf ("\nEnter current > ");
scanf("%f", &I);
R = V / I;

/*** Output Stage for 3 ***/
printf ("\nThe resistance is %.2f ohms\n", R);
printf ("\ndo you want to quit (y/n) > ");
fflush(stdin);
scanf ("%c", &reply);

if (reply == 'y' || reply == 'y')
exit(0);
}

/*** Processing Stage for 0 ***/
else if (choice==0)

{
/*** Output Stage for 0 ***/
printf ("\nQuitting... Hit Any Key to Exit");
fflush(stdin);
getch();
exit(0);
}
}