EECE 1080C / Programming for ECESummer 2022 Laboratory 4: Global Functions Practice

Let's assume that

Q=3.5 coulombs,  ke=15.8 Newtons meters2coulombs2

Write a program that computes the electric field for a user specified value of radius (a) and distance (r). While the program can be written entirely without functions, use the guidelines below to create the required implementation.

Your program should include the following

Global Variables

• define const double variables for the charge and conductivity using the values above

Prototype Declaration

• double askValue(string)
• double eFieldFunction(double, double)
• void printAll(double, double, double)

int Main Scope

• declare two double variables, named distance and radius, initialize by setting each equal to aksValue function, with correct input
• declare one double variable, named eField, initialize by setting equal to eFieldFunction function, with correct input
• call printAll, with the correct inputs, to display the results

Function Definitions

• askValue – create a function to ask the user for the value of local double variable; return that variable. The user should know which parameter to enter based on the input string
• eFieldFunction – create a function to complete the calculation above and store in a local double variable; return that variable. The function should use distance and radius from the input list and use charge and conductivity from the global variables
• printAll – create a function to provide a standard output for this application, the output should look similar to the output solution below. The function should use distance, radius, and electric field from the input list and use charge and conductivity from the global variables

Output Solution

Enter distance: 4.5

Enter radius: 0.3

Gauss's Law for a Conducting Sphere

        Charge (Q):              3.500

        Conductivity (ke):      15.800

        Radius (a):              0.300

        Distance (r):            4.500

        Electric Field (E):      2.731

1. Numerical Extrapolation - Pass-By-Value Exercise

Background

In advanced calculus we may see a derivative that looks like

dydx=1+2xy,  y0=1.0,  0≤x≤5

A numerical solution can be developed that will complete the calculus using simple algebra! The technique is called Runge-Kutta Extrapolation; we start at the coordinate (x=0, y=1) and advance until we reach x=5. The result is a table of xy pairs that make a line.

Don't worry! You do not have to know calculus to solve this problem.

Instead, I will take you through the steps, one piece at a time.

Write a program that generates the xy pairs for the derivative equation and initial condition for 0≤x≤5 using Runge-Kutta Extrapolation.

Your program should include the following:

Prototype Declaration

double step(double, double, int)

• double *ones(int, double = 1)
• double *linspace(double, double, int)
• double dydx(double, double)
• void RungeKutta(double *, double *, int)
• void printXY(double *, double *, int)

int Main Scope

• declare a constant integer to store the number of elements of an array,   use nElem = 11
• declare a double pointer to store the x coordinate, initiailize using the linspace function with inputs, 0, 5, nElem
• declare a double array to store the y coordinate, declare as  y[nElem] = {1.0}
  (note this only sets y[0] = 1, all other values are undefined! This is okay. It is what we want: y0=1.0. The rest will be calculated later.)
• call RungeKutta with inputs x, y, nElem
• call printXY with inputs x, y, nElem

Function Definitions

• step – create a function with input arguments: double L, double H, int N; return the calculation:
  (H-L)(N-1)
• ones – create a function with input arguments: int N, double V; return an array of N elements equal to V
  – initialize the local variable as a pointer     double *A = new double[N]    (matching the output type)
  – use a for loop to assign each element of the array as V      A[i] = V
  – return A
• linspace – create a function with input arguments: double L, double H, int N; return an array of N elements ranging between L and H, equally spaced
  – create a local variable and initialize using the step function                        double s = step(L,H,N)
  – create a local variable as a pointer and initialize using ones function                  double *A = ones(N,L)
  – use a for loop to increment each element of the array                          A[i] += s*i
  – return A
• dydx – create a function with input arguments: double x, double y; return the calculation;
  1+2xy
• RungeKutta – create a function with inputs: double *x, double *y, int N to complete numerical technique, as follows
  – define a local variable and initialize           double h = x[1] - x[0]
  – define four local double variables              double k1, k2, k3, k4
  – start a for loop to advance from 0 to to N-1, then insert five equations… you will need to write the index using [] notation, xi→xi,  yi→yi,  yi+1→y[i+1]
  k1=dydxxi,     yi
  k2=dydxxi+0.5h,     yi+0.5k1h
  k3=dydxxi+0.5h,    yi+0.5k2h
  k4=dydxxi+h,    yi+k3h
  yi+1=yi+h6k1+2k2+2k3+k4
  
  
  
  
  – close the loop
  – (note this is a void function acting on input arrays, changes will automatically apply to the int main scope!)
• printXY – create a function with inputs: double *x, double *y, int N; print a table in the terminal of the results, format and values should match the output solulution

Output Solution

    X         Y

 0.00      1.00

 0.50      1.89

 1.00      4.00

 1.50      8.26

 2.00     15.99

 2.50     28.88

 3.00     48.98

 3.50     78.74

 4.00    120.96

 4.50    178.84

 5.00    255.94

1. Employee Pay Check - Pass-By-Reference Exercise

Background

Workers in the retail space can receive a weekly pay check based on a number of factors:

– salary workers get paid a fixed amount            Salary÷52

– commission workers get paid a variable amount based on the number of products sold             Fee×Units Sold

– hourly workers get paid a fixed rate based on the number of hours they work           Rate×Hour Worked

Write a program that prints out the weekly pay summary, based on user input.

Your program should include the following:

Prototype Declaration

• void askValue(string, char&)
• void askValue(string, string&)
• void askValue(string, int&)
• void askValue(string, double&)
• void workerOptions(char&)
• void salaryPay(double&)
• void commissionPay(double&)
• void hourlyPay(double&)
• void printPayCheck(string&, double&)

int Main Scope

• declare four variables
  • an integer to store the number of workers
  • a string to store the worker's name
  • a character to store the worker's type
  • a double to store the worker's pay
• call askValue to set number                          example            askValue("number of workers", number);
• begin a for loop…(int i = 0; i < number; i++)
  • call askValue to set name                       example            askValue("worker name", name);
  • call workerOptions to set type
  • make a switch-case
    • salary (S) type –call salaryPay to set pay
    • commission (C) type – call commissionPay to set pay
    • hourly (H) type – call hourlyPay to set pay
    • default – set pay to zero
  • call printPayCheck, with correct input

Function Definitions

• askValue (four overloads)– create a function to ask the user for the value the & variable. The user should know which parameter to enter based on string variable; hint: make the first one, copy-paste, and change the type of the second input
• workerOptions - create a function to display the following to the terminal, then calls askValue to set input variable based on user selection

Worker Types

(S) Salary Worker

(C) Commission Worker

(H) Hourly Worker

• salaryPay – create a function that uses a local double variable to store the salary (call askValue to set salary), defines double& input variable as salary÷52
• commissionPay – create a function that uses a local double variable to store the fee (call askValue to set fee), uses a local integer variable to store the units (call askValue to set units), defines the input variable as fee×units sold
• hourlyPay – create a function that uses a local double variable to store the rate (call askValue to set rate), uses a local double variable to store the hours worked (call askValue to set hours worked), defines the input variable as rate×hours worked
• printPayCheck – create a function to print the pay check for the worker, see samples below for standard output; the string& input should represent the worker's name and the double& input should represent the worker's pay

Output Solution

Enter number of workers: 3

Enter worker name: Samuel

Worker Types

(S) Salary Worker

(C) Commission Worker

(H) Hourly Worker

Enter worker type: S

Enter annual salary [RMB]: 85000

.---------------------------------------.

|   C++ Programming Network

|       Pay to the order of Samuel

|               1634 RMB and 6 Jiao

.---------------------------------------.

Enter worker name: Caroline

Worker Types

(S) Salary Worker

(C) Commission Worker

(H) Hourly Worker

Enter worker type: C

Enter commission fee [RMB]: 23.8

Enter units sold: 38

.---------------------------------------.

|   C++ Programming Network

|       Pay to the order of Caroline

|               904 RMB and 3 Jiao

.---------------------------------------.

Enter worker name: Henry

Worker Types

(S) Salary Worker

(C) Commission Worker

(H) Hourly Worker

Enter worker type: H

Enter hourly rate [RMB]: 15.8

Enter hours worked: 36

.---------------------------------------.

|   C++ Programming Network

|       Pay to the order of Henry

|               568 RMB and 8 Jiao

.---------------------------------------.

EECE 1080C / Programming for ECE

Summer 2022