variable is undefined, yet clearly defined in my constructor C++

Question

I have a C++ assignment that requires me to create a class called Tips, that:

has a single member variable, float taxRate
has two constructors, a default that sets taxRate to .65, and a one parameter constructor, that sets taxRate to whatever float the user enters in my tipMain.cpp file.
has only one function, computeTip, that accepts two arguments: totBill and tipRate, both floats that must calculate the before-tax meal cost, and return the tip based on that value and the desired tip rate.

My issue occurs when I attempt to use taxRate inside the computeTip function.

If I use taxRate, computeTip doesn't understand the value of taxRate, stating it is undefined, and even if I do specify tips::taxRate, before I even compile Visual Studio states

Error: a nonstatic member reference must be relative to a specific object.

I vaguely understand this error, but even if I declare taxRate to be static in my .h file, I get LNK2019 errors.

Tips.cpp

#include <iostream>
#include <float.h>
#include "Tips.h"

using namespace std;

Tips::Tips()
{
    taxRate = 0.65;
}

Tips::Tips(float a)
{
    taxRate = a;
}

float computeTip(float totBill, float tipRate)
{
    float mealOnly = 0;
    mealOnly = (totBill/taxRate);       //written both ways to show errors. taxRate undefined here.
    mealOnly = (totBill/Tips::taxRate); //Error: a nonstatic member reference must be relative to a specific object
    return (mealOnly * tipRate);

}

Tips.h

#ifndef Tips_H
#define Tips_H
#include <float.h>

using namespace std;

class Tips
{
public:
    Tips();
    Tips(float);
    float computeTip(float, float, float);
    float taxRate;
};
#endif

and my tipMain.cpp

#include "Tips.h"
#include <iostream>
#include <iomanip>


using namespace std;

float tax;
float meal;
float tip;
void tipProcessor();

int main()
{
    char entry;
    int toggle = 1;
    cout << "Welcome to the Gratuity Calculator!" << endl;
    cout << endl;
    while (toggle != 0)
    {
        cout << "Enter 1 to calculate tip." << endl;
        cout << endl;
        cout << "Enter 2 to exit." << endl;
        cout << endl;
        cout << "Entry: ";
        cin >> entry;
        switch (entry)
        {
        case '1': 
            tipProcessor();
            break;
        case '2': 
            toggle = 0;
            break;
        default: 
            cout << "Enter 1 or 2." << endl;
            cout << endl;
            break;
        }
    }
    system("pause");
    return 0;
}
void tipProcessor()
{
    cout << "Enter bill total: ";
    cin >> meal;
    cout << endl;
    cout << "Enter tax rate: ";
    cin >> tax;
    cout << endl;
    Tips thisTip(tax);
    cout << "Enter tip percent: ";
    cin >> tip;
    cout << endl;
    cout << "Tip is $" << setprecision(4) << thisTip.computeTip(meal, tip, thisTip.taxRate) << "." << endl;
    cout << endl;
}

score 3 · Answer 1 · answered Nov 27 '13 at 16:35

3

You use

float computeTip(float totBill, float tipRate)

But it should be:

float Tips::computeTip(float totBill, float tipRate)

in the implementation. Also you should hide your data members.

answered Nov 27 '13 at 16:35

edmz

8,220
2
26
45

Thank you and all those below you! I knew it was going to be something simple. I swear I'm not special. – user3042535 Nov 28 '13 at 16:53

score 0 · Answer 2 · answered Nov 27 '13 at 16:34

0

You are defining computeTip() as global function, therefore only public static member access is possible. Define as float Tips::computeTip(float ...) and it should compile.

answered Nov 27 '13 at 16:34

Andreas Spindler

7,568
4
43
34

score 0 · Answer 3 · answered Nov 27 '13 at 16:39

0

You've not specified that computeTip is a method of Tips. Change it to this:

float Tips::computeTip(float totBill, float tipRate)
{
    float mealOnly = 0;
    mealOnly = (totBill/taxRate);
    return (mealOnly * tipRate);
}

And all should be well.

answered Nov 27 '13 at 16:39

Sean

60,939
11
97
136

score 0 · Answer 4 · answered Nov 27 '13 at 19:45

Your method declaration and and method definition do not have the same signature. In your header file you indicate that computeTip should take 3 float arguments, but when you define it in the .cpp file, it only takes two arguments.

This is in addition to what other users suggest, prefixing your function with Tips:: to indicate that it is part of the Tips class and thus should be able to access member variables such as taxRate.

Thus your header declaration should look like:

float computeTips(float, float);

And your method definition should look like

float Tips::computeTip(float totBill, float tipRate)
{
...

variable is undefined, yet clearly defined in my constructor C++

4 Answers4