C++ Workshop - Week 6 (Ch. 7) - Quizzes and Exercises - CPP Workshop

Jeromy Walsh · 2008-05-21T20:54:55

Quizzes and Extra Credit for Week 6. Post your answers to the Quizzes from Week 6 here rather than in the chapter thread, so as not to spoil things for the others. Chapter 7 Quiz 1. What does a while-loop cause your program to do? 2. What does the “continue” statement do? 3. What does the “break” statement do? 4. What is it called when you have a loop in which the exit condition can never be met? 5. What loop device do you use if you want to ensure the loop executes at least once, regardless of the success/failure of the test condition? 6. What are the 3 parts to a for-loop header? 7. Can you initialize, test, or perform more than one action within a loop header? If so, what does the syntax look like? 8. Which of the three components of a for-loop header can be left out? 9. According to the new ANSI standard, what is the scope of variables declared in the for-loop header? 10. What types of expressions can be used in a switch statement? 11. What happens if there is no ‘break’ statement at the end of a switch case? 12. Why is it a good idea to always have a default case in a switch statement? Chapter 7 Exercises 1. Guessing Game: Returning to the “guess the number” exercise from week 3, lets now make it a complete game. In your main function generate a random ‘secret’ number using the method shown in week 5 between 1 and 100. Next, repeatedly ask the user to guess the number UNTIL s/he gets the answer correct. Each time they guess let them know whether the number was higher or lower than their guess. Once the user has guessed correctly, let them know and tell them how many guesses it took. 2. Color Menu: In this exercise you are going to write a program that shows the user a menu asking them what color they would like to display their menu in. The menu itself, will be a list of matching numbers and colors. Use the menu below to determine menu options. Present the menu to the user over and over again, allowing them to change the color of the menu until they choose the q option. Once they select ‘q’, terminate the program. There is helper code below to allow you to change the color of the console window. Once the user has selected a color option, set the color for the console window, and then re-print the menu onto the screen. Although not strictly necessary for this exercise, I encourage you to make an enum out of the following menu options and color names, and then use a switch statement to check for color values. The program will work just fine without, however….perhaps try it both ways and see how it’s different in this case. Show the users the following menu: -------------------------------------------- 1. Dark Blue 2. Dark Green 3. Teal 4. Burgundy 5. Violet 6. Gold 7. Silver 8. Gray 9. Blue 10. Green 11. Cyan 12. Red 13. Purple 14. Yellow 15. White Q. Quit Please select a color to display your menu: -------------------------------------------- // To gain access to the functionality required to change the console window colors, add the following include file #include <windows.h> // In function main, call the following line ONCE, to get the handle to the console window HANDLE hConsole = GetStdHandle( STD_OUTPUT_HANDLE ); // To actually SET the color of the console window use the following line of code. SetConsoleTextAttribute( hConsole, COLOR_VALUE ); // where COLOR_VALUE is the color code to set it to Cheers and Good luck!

shawnre

266

June 02, 2007 11:47 AM

Hey JOBe or anyone for that matter, lol

How did you get your code snippets to wrap for long lines? If you look at mine, it made the width of the post extremely wide instead.

Thanks,

Shawn

My Live Space

J0Be

128

June 02, 2007 11:52 AM

Quote: Original post by shawnre
Hey JOBe or anyone for that matter, lol

How did you get your code snippets to wrap for long lines? If you look at mine, it made the width of the post extremely wide instead.

Thanks,

Shawn

Hello shawnre,

I think it's because your comment in your program is to far away from your code, if you then copy it intoo here, you get those long lines.

JWalsh

Author

498

June 02, 2007 11:53 AM

It probably didn't wrap his. He probably inserted a new-line in his code to make the length of the line shorter.

When posting lines of code to the GDNet forums definitely keep it under 80 characters wide.

Cheers!

Jeromy Walsh
Sr. Tools & Engine Programmer | Software Engineer
Microsoft Windows Phone Team
Chronicles of Elyria (An In-development MMORPG)
GameDevelopedia.com - Blog & Tutorials
GDNet Mentoring: XNA Workshop | C# Workshop | C++ Workshop
"The question is not how far, the question is do you possess the constitution, the depth of faith, to go as far as is needed?" - Il Duche, Boondock Saints

Dbproguy

108

May 21, 2008 08:54 PM

Chapter 7 Quiz

1. What does a while-loop cause your program to do?
The while block will execute, while the statement stated in the while statement is true.

2. What does the “continue” statement do?
It will skip the rest of the loop and to back to the beginning of it.

3. What does the “break” statement do?
It skips the rest of the loop and does not loop through that loop again.

4. What is it called when you have a loop in which the exit condition can never be met?
A forever loop

5. What loop device do you use if you want to ensure the loop executes at least once, regardless of the success/failure of the test condition?
do...while

6. What are the 3 parts to a for-loop header?
initialization, test and action

7. Can you initialize, test, or perform more than one action within a loop header? If so, what does the syntax look like?
Yea, for (int i = 0, j = 0; i<3; i++, j++;)

8. Which of the three components of a for-loop header can be left out?
Any

9. According to the new ANSI standard, what is the scope of variables declared in the for-loop header?
Just to the for block

10. What types of expressions can be used in a switch statement?
Any valid C++ expression.

11. What happens if there is no ‘break’ statement at the end of a switch case?
It will fall-through to the next cases.

12. Why is it a good idea to always have a default case in a switch statement?
In case something goes wrong.

Chapter 7 Excercises

1. Guessing Game

[source lang=cpp]#include <stdlib.h>#include <time.h>#include <iostream>using std::cout;using std::cin;using std::endl;int Menu();void Guessing();void ViewResults();int guess;int counter = 1;int randomNum;int main(){	srand( (unsigned)time( NULL ) );	int choice, quit = 0;	while (quit == 0)	{		choice=Menu();		switch (choice)		{		case 1:			Guessing();			break;		case 2:			ViewResults();			break;		case 3:			quit = 1;			break;		default:			cout << "Error. Returning to menu." << endl << endl;			quit = 1;			break;		}	}}int Menu(){	int choice;	cout << "Menu:" << endl;	cout << "(1) Start Playing" << endl;	cout << "(2) View Previous Results" << endl;	cout << "(3) Quit" << endl;	cout << "Choice: ";	cin >> choice;	cout << endl;	return (choice);}void Guessing(){	cout << "Welcome to the Guessing Game!" << endl;	cout << "  by Marcus Johnson" << endl << endl;	randomNum = ( rand() % 100 ) + 1;	cout << "I have generated a random number between 1 and 100." << endl;	cout << "Now I would like you to guess it!" << endl << endl;	for (;guess!=randomNum;counter++)	{		cout << "Guess " << counter << ": ";		cin >> guess;		if (guess > randomNum)			cout << "Oops! Too high!" << endl;		else if (guess < randomNum)			cout << "Oops! Too low!" << endl;		else if (guess == randomNum)			cout << "Good job! It took you " << counter << " guesses." << endl << endl << endl;	}}void ViewResults(){	cout << "Here are your previous results:" << endl;	cout << "It took you " << counter-1 << " tries to guess the number " << randomNum << "." << endl << endl << endl;}

2. Color Menu

[source lang=cpp]#include <windows.h>#include <iostream>using std::cout;using std::cin;using std::endl;enum CHOICE { DARK_BLUE = 1, DARK_GREEN, TEAL, BURGUNDY, VIOLET, GOLD, SILVER, GRAY, BLUE, GREEN, CYAN, RED, PURPLE, YELLOW, WHITE };int main(){	int choice, quit = 0;	HANDLE hConsole = GetStdHandle( STD_OUTPUT_HANDLE );	while (quit == 0)	{		cout << "Menu:" << endl;		cout << "1.  Dark Blue" << endl << "2.  Dark Green" << endl;		cout << "3.  Teal"      << endl << "4.  Burgundy" << endl;		cout << "5.  Violet"    << endl << "6.  Gold" << endl;		cout << "7.  Silver"    << endl << "8.  Gray" << endl;		cout << "9.  Blue"      << endl << "10. Green" << endl;		cout << "11. Cyan"      << endl << "12. Red" << endl;		cout << "13. Purple"    << endl << "14. Yellow" << endl;		cout << "15. White"     << endl << "16.  Quit" << endl;		cout << endl << "Please select the number next to the color to display your menu: ";		cin >> choice;		switch (choice)		{		case 1:  SetConsoleTextAttribute( hConsole, DARK_BLUE ); break;		case 2:  SetConsoleTextAttribute( hConsole, DARK_GREEN ); break;		case 3:  SetConsoleTextAttribute( hConsole, TEAL ); break;		case 4:  SetConsoleTextAttribute( hConsole, BURGUNDY); break;		case 5:  SetConsoleTextAttribute( hConsole, VIOLET); break;		case 6:  SetConsoleTextAttribute( hConsole, GOLD); break;		case 7:  SetConsoleTextAttribute( hConsole, SILVER); break;		case 8:  SetConsoleTextAttribute( hConsole, GRAY); break;		case 9:  SetConsoleTextAttribute( hConsole, BLUE); break;		case 10: SetConsoleTextAttribute( hConsole, GREEN); break;		case 11: SetConsoleTextAttribute( hConsole, CYAN); break;		case 12: SetConsoleTextAttribute( hConsole, RED); break;		case 13: SetConsoleTextAttribute( hConsole, PURPLE); break;		case 14: SetConsoleTextAttribute( hConsole, YELLOW); break;		case 15: SetConsoleTextAttribute( hConsole, WHITE); break;		case 16: quit = 1; break;		default: cout << endl << "Error. Try again" << endl << endl;		}	}}

For that I have a better idea besides using the switch case. Really if you just tested it to be a number somewhere 1 through 15 then just enter that number in the SetConsoleTextAttribute in place of the color name, then test if it's 16 and if it then stop the program.

It seems like it would be so much less code.

--Dbproguy - My Blog - Tips, Opinions and Reviews about C++, Video Games, and Life

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