Homework 6 - More Arrays

Name your files hw6_<problem>.cpp, such as hw6_1.cpp. Email all the cpp files to my account.

1. (10 points) - Convert Homework 5, Problem 2 to use functions instead of having all the menu operations in main(). You will declare an array and an array current size variable in main() and pass it to the functions. The required functions are:
   • get_input - This is a void function which returns nothing. It will have two parameters: an array variable and a by-reference parameter for the current size. It will prompt the user for a filename and try to open that file. If the file open fails, set the current size to 0 and exit the function. Otherwise, read from the file into the array, updating the current size appropriately.
   • calcProduct - This is a calculation function which returns an integer. It will have two parameters: an array variable and a by-value parameter for the current size. It will calculate and return the product of all the elements in the array. If there are no elements in the array, return 0.
   • calcAverage - This is a calculation function which returns a double. It will have two parameters: an array variable and a by-value parameter for the current size. It will calculate and return the average of all elements in the array. If there are no elements in the array, return 0.
   • calcDev - This is a calculation function which returns a double. It will have two parameters: an array variable and a by-value parameter for the current size. It will calculate and return the standard deviation of all elements in the array. If there are less than 2 elements in the array, return 0.
   Update main() to call these functions. For the calculation functions, main() should print the return value to the screen.
2. (10 points) - This program will create a simple employee paycheck calculator using parallel arrays and an array of C-style strings. Use the following menu for the program:

     Welcome to the Employee Paycheck Calculator
     ===========================================
     1.  Add employee record(s) to the database
     2.  Print all employee records
     3.  Print the paycheck for one employee
     4.  Print paychecks for all employees
   
     0.  Exit
     ===========================================
     Enter selection:
   

   Each employee will have three pieces of data: a name, a pay rate and hours worked this pay period. These will be stored in the following parallel arrays:
   • An array of C-style strings to store the employee names.
   • A double array to store the pay rate for each employee.
   • A double array to store the hours worked in this pay period for each employee.
   Each index in the array will correspond to a particular employee, e.g., index 0 of each array will correspond to the first employee. The arrays must all be declared in main()'s scope and passed to the functions. Use a partially filled array for each array, although the current size variable can be shared among all arrays since each array will contain the same number of employees.

   To support each option, main() will make function calls. Before calling the functions for Options 2, 3, and 4, validate that the current number of employees is greater than 0. If it is not, tell the user to select Option 1 first. Do NOT reset the current number of employees after selecting Options 2, 3, or 4.

   For Option 3, you will ask the user to select an index number corresponding to the employee whose paycheck is to be printed out. You MUST validate that the user has selected a valid index number (0 to current size - 1). If the user has selected an invalid index number, print an error message and break out of the select statement (which will trigger the next iteration of the menu loop). When the user has selected a valid index, rather than passing the arrays to the printEmployeePaycheck() function, you will be passing the values at the selected index, e.g., name[0] instead of the whole name array if the user selected index 0.

   You will have at least the following four functions (you may add more functions if you wish) to support the options:

   • addEmployees - This is a void function. It takes four parameters: the array of C-style strings for the name, the array of doubles for the pay rate, the array of doubles for the hours worked and a by-reference parameter for the current number of employees. It will prompt the user for how many employees they wish to add and verify that the requested size is greater than 0 and that the arrays can hold the requested size (e.g., that the requested size is less than or equal to the maximum size of the arrays). It will then loop, prompting the user to enter each employee's name, pay rate and hours worked for the pay period.
   • displayAllEmployees - This is a void function. It takes four parameters: the array of C-style strings for the name, the array of doubles for the pay rate, the array of doubles for the hours worked and a by-value parameter for the current number of employees. It will print all of the employees, using formated output, in a fashion similiar to the following:

     Index  Name               Rate         Hours
     0      John Smith         10.50        40
     1      Jane Doe           10.50        45.5
     2      John Doe            8.90        30.5
     

   • printEmployeePaycheck - This is a void function. It takes three parameters: the C-style string for the employee name, a double for the employee's pay rate, and a double for the hours the employee worked in the current pay period. This prints out the paycheck for a single employee. It should be printed using formated output in a fashion similiar to the following:

     Employee: John Doe         Rate: 8.90     Hours: 30.5     Weekly Pay: $271.45
     

   • printAllPaychecks - This is a void function. It takes four parameters: the array of C-style strings for the name, the array of doubles for the pay rate, the array of doubles for the hours worked and a by-value parameter for the current number of employees. It will loop through all the employees, calling the printEmployeePaycheck() function for each individual employee. The output should resemble:

     Employee: John Smith       Rate: 10.50    Hours: 40       Weekly Pay: $420.00
     Employee: Jane Doe         Rate: 10.50    Hours: 45.5     Weekly Pay: $477.75
     Employee: John Doe         Rate: 8.90     Hours: 30.5     Weekly Pay: $271.45