Thread: Integer variable not working

This is a fairly simple program and everything was fine until i was asked to declare the variable "relays" as an integer after doing so the code does not give me the proper output but if i declare the variable as double it works just fine. what am i missing?

Code:

#include <iostream> //standard library for i/o#include <string>
#include <iomanip>


using namespace std;


int main()
{
    string user_response = "y";
    string cell_num;
    double net_cost;
    double call_tax;
    double total_cost;
    double tax_rate;
    int relays = 0;
    int call_length;


    while (user_response == "y" || user_response == "Y")
    {
        //User Input
        cout << "Please input a cell phone number: ";
        cin >> cell_num;


        cout << "Please input the number of relay stations used: ";
        cin >> relays;


        cout << "\nPlease input the length in minutes of the call: ";
        cin >> call_length;


        
        
        //tax rate based on number of relays
        if ((relays >= 1) && (relays <= 5))
            tax_rate = .01;
        else if ((relays >= 6) && (relays <= 11))
            tax_rate = .03;
        else if ((relays >= 12) && (relays <= 20))
            tax_rate = .05;
        else if ((relays > 21) && (relays <= 50))
            tax_rate = .08;
        else if (relays > 50)
            tax_rate = .12;


        // callculations
        net_cost = ((relays / 50) * 0.40) * call_length;
        call_tax = net_cost * tax_rate;
        total_cost = net_cost + call_tax;


        //Output
        cout << "\nCell Phone:               " << cell_num;


        cout << "\nNumber of Relay Stations: " << relays;


        cout << "\nMinutes Used:             " << call_length; 


        // display cost with a 2 decimal places precision
        cout << setprecision(2) << fixed << "\nNet Cost:                 " << net_cost; 


        cout << setprecision(2) << fixed << "\nCall Tax:                 " << call_tax;


        cout << setprecision(2) << fixed << "\nTotal Cost of Call:       " << total_cost;
        
        cout << "\n\nWould you like to do another calculation (Y or N): \n" << endl;
        cin >> user_response;
    }


    return  0;
}

Your problem is due to "integer division" where the fractional part of the result of a division is discarded. E.g., 27 / 50 is 0 whereas 27.0 / 50.0 is 0.54.

You can leave relays as an int and fix your problem like this:

Code:

        net_cost = ((relays / 50.0) * 0.40) * call_length;

Changing 50 to 50.0 forces the division to be done in floating point instead of integers (relays will be automatically converted to a floating point for the calculation).

Your if/else if's can be simplified like this:

Code:

        if (relays <= 5)
            tax_rate = .01;
        else if (relays <= 11)
            tax_rate = .03;
        else if (relays <= 20)
            tax_rate = .05;
        else if (relays <= 50)
            tax_rate = .08;
        else
            tax_rate = .12;

BTW, unless "callculations" is a pun, you have an extra letter 'l' there!

Thanks for the help and the explanation it will surely help me in the future also not a pun just really tired and didnt noticed :P