Parallel Circuit - c++

Question

I am having trouble with this programming assignment. I need to calculate the value of total resistance for a parallel and series circuit. I have the series circuit functioning, but my problem is that when I try to calculate the total resistance for parallel circuit, my return value is 1.#INF. Any suggestions to how I can fix this
// project.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include <math.h>
using namespace std;
void menu()
{
cout <<"\t\t\tLab 2 Menu Driven Algorithms" << endl;
cout <<"\t\t Calculating Parallel and Series Resistance" << endl;
cout <<"1)\tSeries" << endl;
cout <<"2)\tParallel" << endl;
cout <<"3)\tQuit" << endl;
}
int series(int& num, int& sum)
{
int answer;
num = 0;
sum = 0;
do
{
cout << "Enter Resistor " << num+1 << " value, 0 to calculate: ";
cin >> answer;
cout << endl;
sum = sum + answer;
num++;
}
while(answer != 0);
return sum;
}
double parallel (int& num, double& sum)
{
double answer;
num = 0;
sum = 0.0;
int counter = 0;
do
{
cout << "Enter Resistor " << num+1 << " value, 0 to calculate: ";
cin >> answer;
cout << endl;
counter++;
sum = (1/answer) + sum;
cout << sum << endl;
num++;
}
while(answer != 0);
return sum;
}
int main()
{
char choice;
int num = 0;
int sum = 0;
double sum2 = 0.0;
menu();
cout <<"\n\nPlease enter a value from the menu: ";
cin >> choice;
cout << endl;
while (choice != '3' && choice != 'q' && choice != 'Q')
{
switch(choice)
{
case '1': cout << "Calculating Series Resistance" << endl;
cout << "The series resistance for the " << num-1 << " resistors is: " << series(num, sum) << " Ohms\n";
system("pause");
break;
case '2': cout << "Calculating Parallel Resistance" << endl;
cout << "The parallel resistance for the " << num-1 << " resistors is: " << parallel(num, sum2) << " Ohms\n";
system("pause");
break;
default: break;
}
system("cls");
menu();
cout <<"\n\nPlease enter a value from the menu: ";
cin >> choice;
cout << endl;
}
system("pause");
return 0;
}

Answer 1

You probably want to rewrite the cycle inside the parallel() function this way, so that you will never process a value of 0 (which causes a division by zero in this case):
cout << "Enter Resistor " << num+1 << " value, 0 to calculate: ";
cin >> answer;
cout << endl;
while (answer != 0);
{
counter++; // NOTICE: This is never used for computation...
sum = (1/answer) + sum;
cout << sum << endl;
num++;
cout << "Enter Resistor " << num+1 << " value, 0 to calculate: ";
cin >> answer;
cout << endl;
}
The counter variable is never used for computation, so I guess you could get rid of it.
Also notice, that even the loop inside series() has a similar problem, although the fact that you never cause a division by zero doesn't make it visible.