使用非初始化的变量

我在这里有此代码，除非我们触发'processData'函数，否则我会收到错误

"变量'total pay'正在不被初始化。"

我已经为此工作了几个小时，我的大脑发麻了，任何帮助都将不胜感激。

#include <iostream>
#include <string>
#include <climits>
#include <iomanip>
using namespace std;
// Prototypes
int readInt(string errorMsg = "", int min = INT_MIN, int max = INT_MAX);
void getData(string&, int&, char&, double&);
char getChoice(string prompt, char char1, char char2);
double processData(char service);
void display(string, int, char, double);

// Regular service
const double RCHARGE = 10.00;        // Regular service base rate for first REG_MINS.
const double RPERMIN = 0.20;         // Regular service cost per minute over REG_MINUTES.
const int REG_MINS = 50;             // Regular service free minutes.
// Premium service
const double PCHARGE = 25.00;        // Minimum charge for premium service.
const double P_PER_MIN_DAY = 0.10;   // Charge per day minutes after 75.
const double P_PER_MIN_NIGHT = 0.05; // Charge per night minutes after 100.
const int P_DAY = 75;                // Number of free minutes allowed during the day.
const int P_NIGHT = 100;             // Number of free minutes allowed during the night.
int main()
{
    string name;        // Stores the users name.
    int accountNumber;  // Stores the users account number.
    char serviceType;   // Stores the users service type.
    double minutes;     // Stores the users minutes.
    double totalPay;    // Recieves the total pay from processData.
    bool loopies = true;// Controls the loop while condition is true.

    while (loopies == true)
    {
        getData(name, accountNumber, serviceType, minutes);
        totalPay = processData(serviceType);
        display(name, accountNumber, serviceType, totalPay);
    }

    return 0;
}
// Checks ints to make sure they are valid.
int readInt(string errorMsg, int min, int max)
{
    int someInt;
    bool valid = false;
    do
    {
        // User entering account number
        cin >> someInt;
        // Verifying the data is valid (0 to 9999)
        valid = (someInt >= min && someInt <= max);
        // Clearing out invalid data and prompting for re-entry
        if (cin.fail() || !valid || !isspace(cin.peek()))
        {
            cout << "Error! Invalid input." << endl;
            cout << errorMsg << " must be whole number between " << min << " and " << max << endl;
            cout << "Try Again: ";
            cin.clear(); // Clearing the fail state
            cin.ignore(numeric_limits<streamsize>::max(), 'n');
            valid = false;
        }
    } while (!valid);
    // Clears out following incorrect data once correct
    cin.ignore(100, 'n');
    return someInt;
}
// Takes all user data and checks input.
void getData(string &name, int &account, char &service, double &bill)
{
    cout << "Enter customer name or "Exit" to end program: ";
    getline(cin, name);
    if (name == "Exit" || name == "EXIT" || name == "exit")
    {
        cout << "Program closing..." << endl;
        system("pause");
        exit(EXIT_SUCCESS);
    }
    cout << "Enter account number: ";
    account = readInt("Account", 0, 10000);
    cout << "Enter service type (R for regular or P for premium): ";
    service = getChoice("Service", 'r', 'p' );
}
char getChoice(string input, char char1, char char2)
{
    char character;     // Stores the users character.
    bool valid = false; // Controls the loop.
    do
    {

        cin >> character;
        character = tolower(character);

        valid = (character == char1 || character == char2);

        if (!valid || !isspace(cin.peek())) {
            cout << "Invalid input!" << endl;
            cout << input << " needs to be " << char1 << " or " << char2 << endl;
            cout << "Try again: ";
            cin.clear();
            cin.ignore(numeric_limits<streamsize>::max(), 'n');
            valid = false;
        }
    } while (!valid);
    cin.ignore(100, 'n');
    return toupper(character);
}
double processData(char service)
{
    int dayMin;      // Stores the users day minutes.
    int nightMin;    // Stores the users night minutes.
    double totalPay; // Stores the total pay.
    double dayPay;   // Stores the pay for day minutes.
    double nightPay; // Stores the pay for night minutes.
    if (service == 'r')
    {
        cout << "Enter minutes used: ";
        cin >> dayMin;
        dayMin = readInt("Minutes ", 0, INT_MAX);
        if (dayMin > REG_MINS)
        {
            dayMin -= REG_MINS;
            totalPay = (dayMin * RPERMIN) + RCHARGE;
        }
        else
        {
            totalPay = RCHARGE;
        }
        totalPay = nightPay + dayPay - RCHARGE;
    }
    else if (service == 'p')
    {
        cout << "Enter day minutes: ";
        cin >> dayMin;
        dayMin = readInt("Minutes ", 0, INT_MAX);
        if (dayMin > P_DAY)
        {
            dayMin -= P_DAY;
            dayPay = (dayMin * P_PER_MIN_DAY) + PCHARGE;
        }
        else
        {
            dayPay = PCHARGE;
        }
        cout << "Enter night minutes: ";
        cin >> nightMin;
        nightMin = readInt("Minutes ", 0, INT_MAX);
        if (nightMin > P_NIGHT)
        {
            nightMin -= P_NIGHT;
            nightPay = (nightMin * P_PER_MIN_NIGHT) + PCHARGE;
        }
        else
        {
            nightPay = PCHARGE;
        }
    }
    return totalPay;
}
void display(string name, int account, char service, double bill)
{
    string switchService;
    switch (service)
    {
    case 'R':
        switchService = "Regular";
        break;
    case 'P':
        switchService = "Premium";
        break;
    default:
        cout << "Invalid character.";
    }
    cout << fixed << setprecision(2);
    cout << endl;
    cout << "Customer Name: " << name << endl;
    cout << "Account number: " << account << endl;
    cout << "Service type: " << switchService << endl;
    cout << "Amount due: $" << bill << endl << endl;
}