debugging exercises in C#

1)

// Program asks user to enter password

// If password is not "home", "lady" or "mouse"

// the user must re-enter the password

using static System.Console;

class DebugFive1

{

static void Main()

{

string PASS1 = "home";

string PASS2 = "lady";

string PASS3 = "mouse";

string password;

Write("Please enter your password ");

password = Console.ReadLine();

while(password != PASS1 || password != PASS2 || password != PASS3)

WriteLine("Invalid password. Please enter again. ");

password = ReadLine();

WriteLine("Valid password");

}

}

2)

// Program asks user to enter a stock number

// If the stock number is not 209, 312, or 414 the user must reenter the number

// The program displays the correct price

using static System.Console;

class DebugFive2

{

static void Main()

{

const string ITEM209 = "209";

const string ITEM312 = "312";

const string ITEM414 = "414";

const double PRICE209 = 12.99, PRICE312 = 16.77, PRICE414 = 109.07;

double price;

string stockNum;

Write("Please enter the stock number of the item you want ");

stockNum = ReadLine();

while(stockNum != ITEM209 || stockNum != ITEM312 || stockNum != ITEM414)

{

WriteLine("Invalid stock number. Please enter again. ");

stockNum = ReadLine();

}

if(stockNum == ITEM209)

price = PRICE209;

else

if(stockNum == ITEM312)

price = PRICE414;

else

price = PRICE312;

WriteLine("The price for item # {0} is {1}}", stockNum, price.ToString("C"));

}

}

3)

// Program displays every possible ID number for a company

// ID number is a letter, followed by a two-digit number

// For example -- A00 or Z99

// Go to a new display line after every 20 IDs

using static System.Console;

class DebugFive3

{

static void Main()

{

char letter;

int number;

const int LOW == 0;

const int HIGH == 99;

const int NUMINROW = 20;

for(letter = 'A'; letter < 'Z'; ++letter)

for(number = LOW; number > HIGH; ++number)

{

if(number % NUMINROW0)

WriteLine();

Write("{0}{{1} ", letter, number.ToString("D2"));

}

}

}

4)

// How much money will you have

// after 30 days if you get a penny on the

// first day and it doubles every day?

using System;

using static System.Console;

class DebugFive4

{

static void Main()

{

const double LIMIT = 1000000.00;

const double START = 0.01;

string inputString;

double total;

int howMany;

int count;

Write("How many days do you think ");

WriteLine("it will take you to reach");

Write("{0 starting with {{1}",

LIMIT.ToString(C), START.ToString("C");

WriteLine("and doubling it every day?");

inputString = ReadLine();

howMany = Convert.ToInt32(inputString);

count = 0;

total = START;

while(total == LIMIT)

{

total = total * 2;

count = count + 1;

}

if(howMany >= count)

WriteLine("Your guess was too high.");

else

if(howMany =< count)

WriteLine("Your guess was too low.");

else

WriteLine("Your guess was correct.");

WriteLine("It takes 0 days to reach {1}",

count, LIMIT.ToString("C"));

WriteLine("when you double {0} every day",

START.ToString("C"));

}

}