Calculating employee pay using pass by reference and function overloading - c++

Question

I have not done so well on an assignment for school - I have submitted what is below and I would like to learn and understand more about why my code is terrible lol.
The grading criteria is here
As you can tell, I did not do well at all. I am getting a few errors all related to error C2064: term does not evaluate to a function taking 3 arguments. One of the requirements is using pass by reference. When I attempted that, I had many more errors - so I decided to take it back to something a bit simpler for me and I still cannot see what I am doing wrong.
My instructor specified which parameters we needed to use so I am using those specific ones for each function. The other criterion in writing is below as well as my code.
Again, yes this was for a school assignment, I've already submitted it and got a terrible grade. I would like to have an understanding of what I did wrong and how to correct it so I can learn. Thank you for any and all help.
The weekly gross pay of a salaried employee is calculated by dividing
the employee’s annual salary by 52. Create a named constant variable
to hold and use the value in your overloaded function.
• The weekly gross pay of an Hourly employee is calculated as follows:
If the number of hours worked by the employee is 40 hours or less,
the gross pay is calculated by multiplying the number of hours worked
by the pay rate. If the number of hours worked by the employee
exceeds 40 hours, the employee will receive regular pay for the first
40 hours, and receive time-and-a-half pay for the hours in excess of
40. An hourly employee must not work more than 50 hours per week.
• The weekly gross pay of an intern is calculated by multiplying the
number of hours worked by the pay rate. If an intern works over 15
hours a week, the intern receives time-and-a-quarter pay for the
hours over 15 hours. An intern must not work more than 20 hours per
week.
• The weekly gross pay of a contract employee is calculated by
multiplying the number of hours worked by the pay rate. A contract
employee must not work more than 40 hours per week.
Create four overloaded functions (one each for salaried employee,
hourly employee, contract employee, and Intern) as follows:
 For the Salaried employee function, prompt for two values (employee
number and yearly salary), and pass these two values to the
appropriate function.
 For the Hourly employee function, prompt for three values (employee
number, hours worked and pay rate), and pass these three values to the
appropriate function.
 For the Intern function, prompt for four values (Institution Code,
Department Code, hours worked and pay rate), and pass these four
values to the appropriate function.
• For the Contract employee function, prompt for five values (company
number, project number, employee number, hours worked and pay rate),
and pass these five values to the appropriate function.
For any employee, if more hours than the employee is allowed to work
(based on the type of employee) is entered for number of hours,
reject the input as invalid input, and repeatedly prompt for the valid
range of hours for the employee type until the correct information is
entered.
Continue to request, calculate and display employee information until
there is no more employee data to process. The information displayed
must include all the information collected for each employee and the
calculated weekly pay. Use the end-of-file indicator to terminate
input.
Your program must be able to process zero employees, to an infinite
number of employees. When the program starts, if there is no data to
process during this processing cycle, immediately use the end-of-file
indicator to terminate processing, and display an appropriate
message.
Demonstrate the use of the following in your solution:
• Iteration (Looping)
• Modularity (using functions)
• Function Overloading (use overloaded functions for calculating Gross
Pay)
• Function Prototyping (create a function prototype for each of the
overloaded functions)
• Inter-function communication. To demonstrate inter-function
communication, all prompts for input must occur in the function
main(), all calculated gross pay amounts must be explicitly returned
to the function main(), and all output must be displayed by the
function main(). No output can be displayed by the functions.
• Use of pass-by-reference using Reference arguments. There must be,
at least, one example of pass-by-reference using Reference arguments
with each function in the program, except main(). Your program,
depending on the argument(s) supplied by the user, should invoke the
appropriate overloaded function.*
#include <iostream>
#include <iomanip>
using namespace std;
double grossPay(int number, double hours, double pay); // hourly function
double grossPay(int number, double salary); // salary function
double grossPay(int company, int project, int number, double hours, double pay); // contract function
double grossPay(int institution, int department, double hours, double pay); // intern function
int main() {
// prompt user for type of employee and give EOF instructions.
cout << "Enter '1' for hourly. Enter '2' for salaried." << endl;
cout << "Enter '3' for contracter. Enter '4' for intern." << endl;
cout << "If result is -1, the input was invalid, please input correct employee hours." << endl;
cout << endl;
cout << "Terminate input by using <ctrl> z on Windows then press enter." << endl;
cout << "Terminate input by using <ctrl> z on UNIX / Linux / Mac OS X then press enter." << endl;
int employeeType{ 0 };
int employeeNumber{ 0 };
double grossPay{ 0 };
double overtimePay{ 0 };
// salaried
double employeeSalary{ 0 };
// hourly
double hoursWorked{ 0 };
double payRate{ 0 };
// contractor
int companyNum{ 0 };
int projectNum{ 0 };
// intern
int schoolCode{ 0 };
int departmentCode{ 0 };
while (cin >> employeeType) {
switch (employeeType) {
case 1:
// HOURLY employee prompts and output
cout << "Enter employee number: " << endl;
cin >> employeeNumber;
cout << "Enter number of hours employee worked: " << endl;
cin >> hoursWorked;
cout << "Enter employees pay rate: " << endl;
cin >> payRate;
cout << setprecision(2) << fixed;
cout << "Gross pay of employee including overtime, is $" << grossPay(employeeNumber, hoursWorked, payRate) << endl;
cout << endl;
break;
case 2:
// SALARIED employee prompts and output
cout << "Enter employee number: " << endl;
cin >> employeeNumber;
cout << "Enter employees salary: " << endl;
cin >> payRate;
cout << setprecision(2) << fixed;
cout << "Gross pay of employee" << employeeNumber << "is $" << grossPay(employeeNumber, payRate) << endl;
cout << endl;
break;
case 3:
// CONTRACT employee prompts and output
cout << "Enter company number: " << endl;
cin >> companyNum;
cout << "Enter project number: " << endl;
cin >> projectNum;
cout << "Enter employee number: " << endl;
cin >> employeeNumber;
cout << "Enter number of hours employee worked: " << endl;
cin >> hoursWorked;
cout << "Enter employees pay rate: " << endl;
cin >> payRate;
cout << setprecision(2) << fixed;
cout << "Gross pay of contractor is $" << grossPay(companyNum, projectNum, employeeNumber, hoursWorked, payRate) << endl;
cout << endl;
break;
case 4:
// INTERN prompts and output
cout << "Enter institution code: " << endl;
cin >> schoolCode;
cout << "Enter department code: " << endl;
cin >> departmentCode;
cout << "Enter number of hours employee worked: " << endl;
cin >> hoursWorked;
cout << "Enter employees pay rate: " << endl;
cin >> payRate;
cout << setprecision(2) << fixed;
cout << "Gross pay of intern $" << grossPay(schoolCode, departmentCode, hoursWorked, payRate) << endl;
cout << endl;
break;
}
cout << "Enter '1' for hourly. Enter '2' for salaried." << endl;
cout << "Enter '3' for contracter. Enter '4' for intern." << endl;
cout << endl;
}
cout << endl;
cout << "Thank you for using this program. " << endl;
}
// hourly function
double grossPay(int number, double hours, double pay) {
double hourlyWeek{ 0 };
while (hours > 0 && hours <= 50.00) {
if (hours > 40.00) {
hourlyWeek = ((pay * 40.00) + (hours - 40.00) * (pay * 1.50));
}
else {
hourlyWeek = (hours * pay);
}
}
while (hours > 50.00) {
hourlyWeek = -1;
}
return hourlyWeek;
}
// salary function
double grossPay(int number, double salary) {
double salaryWeek{ 0 };
salaryWeek = (salary * 40);
return salaryWeek;
}
//contractor function
double grossPay(int company, int project, int number, double hours, double pay) {
double contractWeek{ 0 };
while (hours > 0 && hours <= 40.00) {
contractWeek = ((pay * 40.00) + (hours - 40.00) * (pay * 1.50));
}
while (hours > 40.00) {
contractWeek = -1;
}
return contractWeek;
}
// intern function
double grossPay(int institution, int department, double hours, double pay) {
double internWeek{ 0 };
while (hours > 0 && hours <= 20.00) {
if (hours > 15.00) {
internWeek = ((pay * 40.00) + (hours - 40.00) * (pay * 1.25));
}
else {
internWeek = (hours * pay);
}
}
while (hours > 20.00) {
internWeek = -1;
}
return internWeek;
}

Answer 1

rename your local variable:
double grossPay{ 0 };
because you cannot let your variables and function have the same name (grossPay)
by default, the compiler would use virable instead of the method, that's why you got the mistake :)