Assignment 20
Due Tuesday, June 19th at 9:20am on Canvas


Assignment 20.1: Functions Worksheet 4 (10pts)

  • Copy and paste the starter code into a new file called funFunctions4.cpp
  • Write the required functions as described by the prototypes and comments.
  • The functions should be written below main.
  • Then, run the code when you are finished to see if you wrote the functions correctly.
  • Check the test results and make any alterations to your functions as necessary.
  • When all of the tests pass, submit your program.
/**
 *
 * CIS 22A
 */

#include <iostream>
using namespace std;

void deFront(string& str);
//Given a string, remove its first two letters
//deFront("Hello") → "llo"
//deFront("java") → "va"
//deFront("away") → "ay"

void withoutX(string& str);
//Given a string, if the first or last chars are 'x' or 'X',
//remove those 'x'/'X' chars. Otherwise, leave the string unchanged
//withoutX("xHix") → "Hi"
//withoutX("xHi") → "Hi"
//withoutX("Hxix") → "Hxi"

void spaceToComma(string& list);
//Given a string, alters any blank spaces in the string
//to be commas. Hint: Use a for loop, and string indexing
//spaceToComma("cats hats bats") -> "cats,hats,bats"
//spaceToComma("I love cookies! ") -> "I,love,cookies!,"

void plusOut(string& str);
//Given a string, converts any number in the string to a '+'
//Hint: Use a for loop, and string indexing
//plusOut("123 East 9th St")-> "+++ East +th St"
//plusOut("Agent 007")-> "Agent +++"

void remove1At(string& str);
//Given a string, replace an i or I character with a 1
//and any a or A character with the @ sign.
//Hint: use a for loop, and string indexing
//remove1At("Hi, Brad") -> "H1, Br@d"
//remove1At("I love fun AND games") -> "1 love fun @ND g@mes"

int main() {
    int result;
    bool answer;
    string value, str;

    cout << boolalpha << "***Testing deFront***" << endl << endl;
    value = "Hello";
    deFront(value);
    cout << "Should print llo: " << value << endl;
    value = "java";
    deFront(value);
    cout << "Should print va: " << value << endl;
    value = "away";
    deFront(value);
    cout << "Should print ay: " << value << endl;

    cout << boolalpha << "***Testing withoutX***" << endl << endl;
    value = "xHix";
    withoutX(value);
    cout << "Should print Hi: " << value << endl;
    value = "xHi";
    withoutX(value);
    cout << "Should print Hi: " << value << endl;
    value = "Hxix";
    withoutX(value);
    cout << "Should print Hxi: " << value << endl;

    cout << "***Testing spaceToComma***" << endl << endl;
    str = "cats hats bats";
    spaceToComma(str);
    cout << "Should be cats,hats,bats: " << str << endl;
    str = "I love cookies! ";
    spaceToComma(str);
    cout << "Should be I,love,cookies!,: " << str << endl << endl;

    cout << "***Testing plusOut***" << endl << endl;
    str = "123 East 9th St";
    plusOut(str);
    cout << "+++ East +th St: " << str << endl;
    str = "Agent 007";
    plusOut(str);
    cout << "Should be Agent +++: " << str << endl << endl;

    cout << "***Testing remove1At***" << endl << endl;
    str = "Hi, Brad";
    remove1At(str);
    cout << "Should print H1, Br@d: " << str << endl;
    str = "I love fun AND games";
    remove1At(str);
    cout << "Should print 1 love fun @ND g@mes: " << str << endl << endl;

    cout << "***End of Tests***" << endl;

    return 0;

}

Assignment 20.2: Restaurant Math (10 pts)
  • Write a program to help you calculate your bill at a restaurant.
  • Name your program restaurant.cpp.
  • For this program, you will need to write 4 functions, as follows:

calculateBill
  • Takes in a double reference parameter for the price of the food.
  • Takes in a double value parameter for the chosen tip percent
  • calls the addTax function to add taxes to the price.
  • calls the calculateTip function to add the tip to the price.
  • calls the formatPrice function to print out the price
  • returns nothing

addTax

  • Takes in a double reference parameter for the price of the food.
  • Updates the price by adding on the tax, assuming the tax rate is 9.25% in Santa Clara County
  • returns nothing

calculateTip

  • Takes in a double reference parameter for the current bill (price + tax).
  • Takes in a second double - this time a value parameter - for the percent tip.
  • Calculates the amount of the tip and updates the current price by adding on the tip amount
  • returns nothing

formatPrice

  • Takes in a double value parameter for the price.
  • prints the price in the form $X.XX
  • (Hint: How do you get the price to have only 2 decimal values?)
  • Also prints a message about the final price: "With tax and tip, your total comes to... $<price>"
  • returns nothing

Additional Specifications

  • You must include function prototypes at the top of your program.
  • Each prototype must also have a comment in the style described in class.
  • You should write the full function definitions below main.
  • Important: You should call the calculateBill function inside of main, not the other three functions.
  • The other 3 functions should be called inside of the calculateBill function.

Starter Code:

  • Below is the starter code for this assignment.
  • Important: Do NOT change the code in any way. You should simply add your three additional functions to it.
  • Also important: Do NOT add anything to main and do not alter main.
  • Your program should work identically to mine without making any changes to main.
  • Note that calculateTip will work similarly to the addTax function, except you will have to use the chosen tip amount in your calculations.


void addTax(double& price);
//calculates the tax at 9.25% and adds it to the price of the meal

void calculateBill(double& price, double percent);
//calls addTax, calculateTip and displayPrice
//to calculate and display the final price


int main()
{
    cout << "Welcome to the Restaurant Calculator\n";
    cout << "\nEnter the price of your meal: ";
    double price;
    cin >> price;
    double percent;
    cout << "Enter the percent tip (10-25): ";
    cin >> percent;
    calculateBill(price, percent);
    cout << "Goodbye!";

}

void addTax(double& price)
{
    price *= 1.0925;

}


void calculateBill(double& price, double percent)
{
    addTax(price);
    //add two additional function calls here

}

  • Your program should  now work identically to the following:
Welcome to the Restaurant Calculator!

Enter the price of your meal: 25.99

Enter the percent tip (10-25): 20

With tax and tip, your total comes to... $34.07
Goodbye!

  • However, there is a potential problem we have not accounted for in our program. What if the user enters a string instead of a double for the meal cost and the percent tip.
  • Add in two while loops into your program to check for cin failure.
  • Print an appropriate error message to the user as shown below.
  • When you are finished your program should work identically to the following:

Sample Output

  • When your program works identically to the output below, submit it to Canvas.
Welcome to the Restaurant Calculator

Enter the price of your meal: twenty-five ninety-nine
Please enter numbers not letters.

Enter the price of your meal: twenty-five dollars and ninety-nine cents!
Please enter numbers not letters.

Enter the price of your meal: $25.99
Please enter numbers not letters.

Enter the price of your meal: 25.99

Enter the percent tip (10-25): twenty
Please enter numbers not letters.

Enter the percent tip (10-25): twenty percent!
Please enter numbers not letters.

Enter the percent tip (10-25): I said twenty percent!!!
Please enter numbers not letters.

Enter the percent tip (10-25): 20

With tax and tip, your total comes to... $34.07
Goodbye!

Assignment 20.3: Barnyard Animals (10 pts)
  • In this assignment we write a program that copies five numbers from an input stream to an output stream.
  • Copy the following program into a C++ file, save it as animals.cpp, and then compile and run the starter program to make sure you copied it correctly. 
    #include <iostream>
using namespace std;

int main() {
    // Enter your code here

    return 0;
}
  • Then, let's create a text file to test our program.
  • If you are using Eclipse (strongly encouraged for File I/O!), right-click the project folder and select New->File. Name your file infile.txt.
  • Make sure that you did not accidentally save your file under the src folder. If you did, you can simply drag and drop it into the main project folder.
  • If you are using another IDE, such as Xcode, you will need to research where to save your files using a Google search. It is more challenging in Xcode and the instructor is not able to provide you with the support you need.
  • Therefore, you may also choose to do this assignment on the ATC 203 lab computers. You can also search for tutorial videos on Youtube to help you.
  • Here are the values to place in your file.
5
3
8
2
4

  • We will read from this file after writing our program.

  • Add the following new libraries that you need to your source code file: 
    #include <fstream>   // for file I/O
#include <cstdlib>   // for exit()
  • Inside main(), declare an input stream variable named fin and an output stream variable named fout.
  • Add code to connect each stream to a file using open() and check for failure:
  • Name your output file outfile.txt
  • Add statements to read two numbers from the input stream.
  • For example, here is possible code for reading the first number: 
    int first;
fin >> first;
  • Add 4 more pairs of statements like the ones above to read in the next 4 numbers.
  • Then, add an fout statement to print out a title at the top of your file
    fout << "Animals at our farm" << endl;
  • Next, write out the contents of your five variables to the file. For example:
fout << first << " chickens" << endl;
  • Add 4 more statements like the one above, so that your file contains the following when you are finished:
Animals at our farm
5 chickens
3 cows
8 ducks
2 horses
4 pigs
  • Close the streams when finished reading and writing: 
    fin.close();
fout.close();
  • Compile and run your program to make sure you made the changes correctly.
  • Notice that you do not see any output on the console screen. The output stream wrote the program output to the output file.
  • Open the output file you created and verify that your file contains the following:

    Animals at our farm
    5 chickens
    3 cows
    8 ducks
    2 horses
    4 pigs
  • Submit your program to Canvas when you are finished