Appendix 2 - Sample solutions
This appendix contains sample code listings for the exercises referenced in the text. They are to be regarded as examples of possible solutions and not definitive. When programming a solution there is often more than one way to arrive at a workable answer.
Solutions do not, or rarely, include concepts covered in later chapters.
Chapter 1
Write a program to calculate the area of a triangle
| using System;
namespace triangle
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Calculate the area of a triangle");
int height;
int width;
double area;
Console.Write("Enter the height of the triangle > ");
height = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter the width of the triangle > ");
width = Convert.ToInt32(Console.ReadLine());
area = height * width;
Console.WriteLine($"The triangle's area is {area} units");
Console.WriteLine("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Chapter 2
Write a program that converts a temperature in degrees Fahrenheit into Centigrade/Celsius
| using System;
namespace TempConv
{
class Program
{
static void Main(string[] args)
{
double fahrTemp;
double celTemp;
Console.Clear();
Console.WriteLine("Temperature Conversion");
Console.Write("Enter a temperature in degrees Fahrenheit > ");
fahrTemp = Convert.ToDouble(Console.ReadLine());
celTemp = (fahrTemp - 32) * 5/9;
Console.WriteLine($"{fahrTemp} degrees F is {celTemp} degrees C");
Console.WriteLine("Press any key to continue ...");
Console.ReadKey();
}
}
}
|
Declare two variables of type int. Assign them the values \(8\) and \(5\). Swap their values and print them to the screen
| using System;
namespace swap
{
class Program
{
static void Main(string[] args)
{
int first = 8;
int second = 5;
Console.Clear();
Console.WriteLine("Simple swap");
Console.WriteLine($"Before the swap: First = {first}, Second = {second}");
int Temp = first;
First = second;
second = Temp;
Console.WriteLine($"After the swap: First = {first}, Second = {second}");
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Write a program which inputs the length and width of a rectangular garden. Calculate the area of the garden and the cost of turfing a lawn if a 1m unturfed border is around the perimeter of the garden. Assume the cost of turf is 10 per square metre
| using System;
namespace Turf
{
class Program
{
static void Main(string[] args)
{
const int costPerSqMetre = 10;
double length;
double width;
double lawnArea;
double cost;
Console.WriteLine("How much to turf a lawn?");
Console.Write("Enter length of the lawn > ");
length = Convert.ToDouble(Console.ReadLine());
Console.Write("Enter width of the lawn > ");
width = Convert.ToDouble(Console.ReadLine());
lawnArea = (length - 2) * (width-2);
cost = lawnArea * costPerSqMetre;
Console.WriteLine($"Total cost = ${cost}");
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Chapter 3
Displaying a pack of cards
To avoid repetition in the code, this solution uses two methods (see Chapter 9) to return a string representation of the playing card, GetRankAsString() and GetSuitAsString().
| using System;
namespace cards
{
class Program
{
static void Main(string[] args)
{
string rank = "";
string suit = "";
Console.Clear();
Console.WriteLine("Cards Complete");
// Pick a card
Console.Write("Enter a number (1-52) to pick a card from the deck, or 0 to select a random card > ");
int myCardNum = Convert.ToInt32(Console.ReadLine());
if (myCardNum == 0)
{
Random rnd = new Random();
myCardNum = rnd.Next(52);
}
rank = GetrankAsString(m - 1); // -1 to ensure first card can be selected
suit = GetsuitAsString(m);
Console.WriteLine($"Your card is the {rank} of {suit}");
Console.WriteLine("The whole deck ...");
for (int i = 0; i < 52; i++)
{
//rankNum = (i % 13) + 1;
//suitNum = i / 13;
rank = GetrankAsString(i);
suit = GetsuitAsString(i);
Console.WriteLine($"{rank} of {suit}");
}
Console.WriteLine("Press any key to continue ...");
Console.ReadKey();
}
static string GetrankAsString(int rank)
{
int rankNum = (rank % 13) + 1;
string rankStr = "";
switch (rankNum)
{
case 1:
rankStr = "Ace";
break;
case 2:
rankStr = "Two";
break;
case 3:
rankStr = "Three";
break;
case 4:
rankStr = "Four";
break;
case 5:
rankStr = "Five";
break;
case 6:
rankStr = "Six";
break;
case 7:
rankStr = "Seven";
break;
case 8:
rankStr = "Eight";
break;
case 9:
rankStr = "Nine";
break;
case 10:
rankStr = "Ten";
break;
case 11:
rankStr = "Jack";
break;
case 12:
rankStr = "Queen";
break;
case 13:
rankStr = "King";
break;
}
return rankStr;
}
static string GetsuitAsString(int suit)
{
string suitStr = "";
int suitNum = suit / 13;
if (suitNum == 0)
suitStr = "\u2663"; // club
else if (suitNum == 1)
suitStr = "\u2666"; // diamond
else if (suitNum == 2)
suitStr = "\u2665"; // heart
else if (suitNum == 3)
suitStr = "\u2660"; // spades
else
suitStr = "ERROR";
return suitStr;
}
}
}
|
Using a bitwise operator write a program that checks if an integer is odd or even
| using System;
namespace oddOrEven
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Odd Or Even");
Console.Write("Enter a number > ");
int value = Convert.ToInt32(Console.ReadLine());
if ((value & 1) == 1)
Console.WriteLine($"{value} is odd");
else
Console.WriteLine($"{value} is even");
Console.WriteLine("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Write a program that takes as input a four digit number and calculates the sum of the digits
| using System;
namespace sumOfDigits
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Sum Of Digits");
Console.Write("Enter a number with 4 digits only > ");
string numString = Console.ReadLine();
int sum = 0;
sum += Convert.ToInt32(numString[0]) - '0'; // input is in ASCII, need to subtract 48, or '0'
sum += Convert.ToInt32(numString[1]) - 48;
sum += Convert.ToInt32(numString[2]) - '0';
sum += Convert.ToInt32(numString[3]) - '0';
Console.WriteLine($"Sum is {sum}");
sum = 0;
// alternatively a loop would help
for (int i = 0; i < numString.Length; i++)
sum += numString[i] - 48;
Console.WriteLine($"The looped sum is also {sum}");
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Chapter 4
Returning the minimum and maximum of two values (not conditionals)
| using System;
namespace max
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Max without an IF");
int first = 8;
int second = 5;
Console.WriteLine($"Smaller of ({first},{second}) is {Math.Min(first,second)}");
Console.WriteLine($"Larger of ({first},{second}) is {Math.Max(first,second)}");
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Printing in columns
| using System;
namespace columns
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Printing in columns");
int first = 0xFF;
double second = 245.7689;
double third = -123.456;
Console.WriteLine($"|0x{first,-8:X}|{second,-10:f2}|{third,-10:f2}|");
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Chapter 5: Making Decisions
Rock, Paper, Scissors
| using System;
namespace rockPaperScissors
{
class Program
{
static void Main(string[] args)
{
string computerObject = "";
int computerChoice = 0;
bool computerWins = false;
Random random = new Random();
Console.Clear();
Console.Write("Enter your choice r(ock), p(aper), s(cissors): ");
string userObject = Console.ReadLine();
char userObjectFirst = userObject[0]; // get first character of user choice
computerChoice = random.Next(3); // get random value, 0..2, for selecting computer choice
switch (computerChoice)
{
case 0:
computerObject = "rock";
break;
case 1:
computerObject = "paper";
break;
case 2:
computerObject = "scissors";
break;
}
char computerObjectFirst = computerObject[0];
Console.WriteLine("Computer chose: " + computerObject);
if (String.Equals(computerObjectFirst, userObject))
{
Console.WriteLine("It's a draw!");
}
else
{
if (computerObjectFirst == 'r' && userObjectFirst == 'p')
{
computerWins = false;
}
else if (computerObjectFirst == 'r' && userObjectFirst == 's')
{
computerWins = true;
}
else if (computerObjectFirst == 's' && userObjectFirst == 'r')
{
computerWins = false;
}
else if (computerObjectFirst == 's' && userObjectFirst == 'p')
{
computerWins = true;
}
else if (computerObjectFirst == 'p' && userObjectFirst == 'r')
{
computerWins = true;
}
else if (computerObjectFirst == 'p' && userObjectFirst == 's')
{
computerWins = false;
}
if (computerWins == true)
{
Console.WriteLine("Computer has won!");
}
else
{
Console.WriteLine("You have won!");
}
}
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Leap Year
| using System;
namespace leapyear
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Leap year");
int year;
bool leapyear = false;
Console.Write("Enter a valid year: ");
year = Convert.ToInt32(Console.ReadLine());
if ((year % 4 == 0) && (year % 100 != 0))
{
leapyear = true;
}
else if (year % 100 == 0)
{
if (year % 400 == 0)
{
leapyear = true;
}
}
if (leapyear)
{
Console.WriteLine(year + " is a leap year");
}
else
{
Console.WriteLine(year + " is not a leap year");
}
}
}
}
|
Roots of a quadratic equation
| using System;
namespace quadratic
{
class Program
{
static void Main(string[] args)
{
int a, b, c;
double discriminant;
double x1, x2;
Console.Clear();
Console.WriteLine("Quadratic Equation Solver");
Console.Write("Enter first value (a) > ");
a = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter second value (b) > ");
b = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter third value (c) > ");
c = Convert.ToInt32(Console.ReadLine());
discriminant = Math.Pow(b,2) - (4 * a * c);
if (a == 0)
{
Console.WriteLine("Not quadratic");
}
if (discriminant == 0)
{
x1 = -b/(2.0*a);
x2 = x1;
Console.WriteLine($"Both roots are equal: {x1}");
}
else if (discriminant > 0)
{
Console.WriteLine("There are two real roots");
x1 = (-b + Math.Sqrt(discriminant))/(2 * a);
x2 = (-b - Math.Sqrt(discriminant))/(2 * a);
Console.WriteLine($"First root = {x1}");
Console.WriteLine($"Second root = {x2}");
}
else
{
Console.WriteLine("There are no roots");
}
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Chapter 6: Iteration
Display table of ASCII codes (32-126)
| using System;
namespace ascii
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("ASCII Table of printable characters\n");
Console.WriteLine("+----------+------------+-----------+");
Console.WriteLine("| Decimal | Hex | Character |");
Console.WriteLine("+----------+------------+-----------+");
for (int i = 32; i < 126; i++)
{
Console.WriteLine($"|{i,9} | {i,10:X} | {(char)i,10}|");
}
Console.WriteLine("+----------+------------+-----------+");
Console.WriteLine("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Fizz Buzz
| using System;
namespace fizzbuzz
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Fizz Buzz");
for (int i = 1; i <= 100; i++)
{
if ((i % 5 == 0) && (i % 3 == 0))
{
Console.WriteLine(i + " FIZZ BUZZ");
}
else if (i % 3 == 0)
{
Console.WriteLine(i + " FIZZ");
}
else if (i % 5 == 0)
{
Console.WriteLine(i + " BUZZ");
}
else
{
Console.WriteLine(i);
}
}
Console.WriteLine("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Sum the first \(N\) numbers of the Fibonacci series
| using System;
namespace fibonacci
{
class Program
{
static void Main(string[] args)
{
int number;
int sum = 0;
int temp = 0;
int first = 0;
int next = 1;
Console.Clear();
Console.WriteLine("sum of Fibonacci numbers to N");
Console.Write("Enter a number: ");
number = Convert.ToInt32(Console.ReadLine());
Console.Write($"[ {temp} ");
for (int i = 1; i < number; i++)
{
first = next;
next = temp;
temp = first + next;
Console.Write($"{temp} ");
sum += temp;
}
Console.WriteLine("]");
Console.WriteLine($"The sum of the first {number} numbers in Fibonacci sequence is {sum}");
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Chapter 7: Arrays
Initialise an array with square numbers
| using System;
namespace squareArray
{
class Program
{
static void Main(string[] args)
{
const int LENGTH = 20;
int[] myArray = new int[LENGTH];
Console.Clear();
Console.WriteLine("Initialising an array with square numbers");
for (int i = 0; i < LENGTH; i++)
{
myArray[i] = i * i;
}
foreach(int element in myArray)
{
Console.Write($"{element} ");
}
Console.WriteLine();
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Searching for an element in an array
| using System;
namespace randomSearch
{
class Program
{
static void Main(string[] args)
{
const int MIN = 0;
const int MAX = 100;
const int NUM_ELEMENTS = 20;
int[] myArray = new int[NUM_ELEMENTS];
int searchKey;
bool found = false;
Random rnd = new Random();
Console.Clear();
Console.WriteLine("Searching for a value in an array");
// initialise array
for (int i = 0; i < myArray.Length; i++)
{
myArray[i] = rnd.Next(MIN,MAX);
}
// ask use for a search value/key
Console.Write("Enter a value to find: ");
searchKey = Convert.ToInt32(Console.ReadLine());
foreach (int e in myArray)
{
//Console.Write($"{e} "); // testing
if (e == searchKey)
{
found = true;
break; // only need first instance
}
}
// print result
if (found)
{
Console.WriteLine($"\nYour value {searchKey} was found!");
}
else
{
Console.WriteLine($"\nYour value {searchKey} could not be found");
}
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Merge two arrays
| using System;
namespace merge
{
class Program
{
static void Main(string[] args)
{
const int SIZE = 10;
const int MIN = 0;
const int MAX = 100;
int[] firstArray = new int[SIZE];
int[] secondArray = new int[SIZE];
int[] mergedArray = new int[SIZE * 2];
Console.Clear();
Console.WriteLine("Merge two arrays");
Random rnd = new Random();
// initialise starting arrays with random values
int i;
for (i = 0; i < SIZE; i++)
{
firstArray[i] = rnd.Next(MIN,MAX);
SecondArray[i] = rnd.Next(MIN,MAX);
}
// merge into a new array
for (i =0; i < SIZE; i++)
{
mergedArray[i] = firstArray[i];
}
for(int j = 0; j < SIZE; j++)
{
mergedArray[i] = SecondArray[j]; // note value for i
i++;
}
Array.Sort(mergedArray);
// Print arrays
Console.WriteLine("nFirst array");
// first array
foreach(int e in firstArray)
{
Console.Write($"{e} ");
}
Console.WriteLine("\nSecond array");
foreach(int e in SecondArray)
{
Console.Write($"{e} ");
}
Console.WriteLine("\nMerged array");
// print merged array
foreach(int el in mergedArray)
{
Console.Write($"{el} ");
}
Console.WriteLine();
Console.Write("Press any key to quit ...");
Console.ReadKey();
}
}
}
|
Multiplication table
| using System;
namespace multiplicationTable
{
class Program
{
static void Main(string[] args)
{
const int START = 1;
const int END = 12;
Console.Clear();
Console.WriteLine("Multiplication Table");
// header row
Console.Write($" ");
for(int i = 1; i <= END; i++)
{
Console.Write($" {i,5} ");
}
// multiplication table
for (int row = START; row <= END; row++)
{
Console.Write($"{row,3} | ");
for (int col = START; col <= END; col++)
{
Console.Write($" {row * col,5} ");
}
Console.WriteLine();
}
}
}
}
|
Chapter 8: Strings, Encryption and Testing
Searching for keywords
| using System;
namespace stringChecking
{
class Program
{
static void Main(string[] args)
{
string str = "I am going to check every word of this sentence for the keywords";
string[] words;
Console.Clear();
Console.WriteLine("String Checking");
words = str.Split(' ');
foreach(string w in words)
{
if ((w == "check") || (w == "word") || (w == "sentence"))
{
Console.ForegroundColor = ConsoleColor.DarkRed;
Console.Write($"{w} ");
Console.ForegroundColor = ConsoleColor.Black;
}
else
{
Console.Write($"{w} ");
}
}
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Counting characters
| using System;
namespace countCharacters
{
class Program
{
static void Main(string[] args)
{
int[] charFrequency = new int[26];
string inputString;
Console.Clear();
Console.WriteLine("Counting characters");
Console.Write("Enter a string: ");
inputString = Console.ReadLine();
inputString = inputString.ToUpper();
for(int i = 0; i < inputString.Length; i++)
{
// only counting letters, not punctuation
if ((inputString[i] >= 'A') && (inputString[i] <= 'Z'))
{
charFrequency[inputString[i]-'A']++;
}
}
// print, getting the character represented by each index followed by the value
for (int i = 0; i < charFrequency.Length; i++)
{
Console.Write((char)(i+65) + ": " + charFrequency[i] + " ");
}
Console.WriteLine();
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Screen scraping
| using System;
namespace screenScrape
{
class Program
{
static void Main(string[] args)
{
string html = "<html><head><title>News</title></head><body><p>Getting proficient with C# requires <b>practice</b>, <b>practice</b> and more <b>practice</b></p></body></html>";
string output = String.Empty;
bool openingTagMode = false;
Console.Clear();
Console.WriteLine("Screen scraping");
for (int i = 0; i < html.Length; i++)
{
if (html[i] == '<')
{
openingTagMode = true;
}
else if (html[i] == '>')
{
openingTagMode = false;
}
if ((!openingTagMode) && (html[i] != '>'))
{
output += html[i];
}
}
Console.WriteLine(output);
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Chapter 9 - Methods
Calculator
| using System;
namespace calculator
{
class Program
{
static void Main(string[] args)
{
int menuOption;
Console.Clear();
Console.WriteLine("Welcome to the calculator program\n");
do
{
// Ask the user for two number and store them as floats
Console.Write("Enter the first number: ");
float number1 = GetFloat();
//float number1 = float.Parse(Console.ReadLine());
Console.Write("Enter the second number: ");
float number2 = GetFloat();
//float number2 = float.Parse(Console.ReadLine());
// Output the menu options
Console.WriteLine("\nEnter the menu number of the calculation to perform: ");
Console.WriteLine("1 - Addition");
Console.WriteLine("2 - Subtraction");
Console.WriteLine("3 - Multiplication");
Console.WriteLine("4 - Division");
Console.WriteLine("5 - Modulus");
Console.WriteLine("6 - Floor Division");
Console.WriteLine("7 - QUIT\n");
// Ask for the menu option
menuOption = GetInt();
switch (menuOption)
{
case 1:
Console.WriteLine($"The result = {Addition(number1, number2)}");
break;
case 2:
Console.WriteLine($"The result = {Subtraction(number1, number2)}");
break;
case 3:
Console.WriteLine($"The result = {Multiplication(number1, number2)}");
break;
case 4:
Console.WriteLine($"The result = {Division(number1, number2)}");
break;
case 5:
Console.WriteLine($"The result = {Modulus(number1,number2)}");
break;
case 6:
Console.WriteLine($"The result = {Floor(number1, number2)}");
break;
}
} while ((menuOption >= 1) && (menuOption <= 6));
}
// The addition procedure has two floats as parameters, adds them together and outputs the result
static float Addition(float num1, float num2)
{
return num1 + num2;
}
static float Subtraction(float num1, float num2)
{
return num1 - num2;
}
static float Multiplication(float num1, float num2)
{
return num1 * num2;
}
static float Division(float num1, float num2)
{
if (num2 != 0)
return num1 / num2;
else
return -1;
}
static float Modulus(float num1, float num2)
{
return num1 % num2;
}
static int Floor(float num1, float num2)
{
//Console.WriteLine(Math.Floor(Division(num1,num2)));
if (((num1 < 0) ^ (num2 < 0)) && (num1 % num2 != 0))
{
return Convert.ToInt32(num1/num2);
}
else
{
return Convert.ToInt32(num1 / num2)-1;
}
}
static float GetFloat()
{
string input = Console.ReadLine();
float result = 0f;
while (!float.TryParse(input, out result))
{
Console.WriteLine("That is not a valid number, please try again.");
Console.Write("Enter number > ");
input = Console.ReadLine();
}
return result;
}
static int GetInt()
{
string input = Console.ReadLine();
int result = 0;
while (!Int32.TryParse(input, out result))
{
Console.WriteLine("That is not a valid number, please try again.");
Console.Write("Enter number > ");
input = Console.ReadLine();
}
return result;
}
}
}
|
Secret Word
| using System;
namespace secretWord
{
class Program
{
static void Main(string[] args)
{
// Initialise the variables and secret word
int menuOption;
string secretWord = "Computer";
do
{
Console.Clear();
// Output the menu
Console.WriteLine("\nWelcome to the guessing program menu - choose your option:");
menuOption = GetMenuOption();
// Choose a task depending on the menu option
switch (menuOption)
{
case 1:
// Change the secret word
secretWord = ChangeSecretWord();
break;
case 2:
// Guess the secret word
GuessSecretWord(secretWord);
break;
case 3:
// Quit the program
Exit();
break;
default:
Console.WriteLine("Invalid menu choice");
break;
}
}
while (menuOption >= 1 && menuOption <= 2);
}
static int GetMenuOption()
{
Console.WriteLine("MAIN MENU\n");
Console.WriteLine("1 - Change the secret word");
Console.WriteLine("2 - Make a guess");
Console.WriteLine("3 - Quit");
Console.Write("> ");
// Ask the user for the menu number
return (GetInt());
}
static string ChangeSecretWord()
{
Console.WriteLine("What is the new secret word?");
Console.Write("> ");
return Console.ReadLine();
}
static void GuessSecretWord(string secretWord)
{
Console.Write("Guess the secret word: ");
string guess = Console.ReadLine();
// Check whether the word entered was the secret word - ignoring case
if (guess.ToUpper() == secretWord.ToUpper())
{
Console.WriteLine("Well done - you have guessed the secret word!");
}
else
{
Console.WriteLine("Sorry, that is not the secret word");
}
PressAnyKey();
}
static void Exit()
{
Console.WriteLine("Thank you for playing secret word");
Environment.Exit(0);
}
static void PressAnyKey()
{
Console.Write("Press any key to continue...");
Console.ReadKey();
}
static int GetInt()
{
string input = Console.ReadLine();
int result = 0;
while (!Int32.TryParse(input, out result))
{
Console.WriteLine("That is not a valid option, please try again.");
Console.Write("> ");
input = Console.ReadLine();
}
return result;
}
}
}
|
Binary to decimal 'bitwise' converter
| using System;
namespace binaryToDecimal
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Binary to decimal bitwise converter");
string binary = GetBinaryValue();
int result = ConvertBinary(binary);
OutputResult(result);
Exit();
}
static string GetBinaryValue()
{
Console.WriteLine("Enter binary number to be converted");
Console.Write("> ");
return Console.ReadLine();
}
static int ConvertBinary(string binary)
{
int column = 128;
int result = 0;
for (int i = 0; i < binary.Length; i++)
{
int bitValue = ConvertBit(binary[i],column);
column /= 2;
result += bitValue;
}
return result;
}
static int ConvertBit(char bit, int col)
{
int result = 0;
if (bit == '1')
{
result += col;
}
return result;
}
static void OutputResult(int result)
{
Console.WriteLine(result);
}
static void Exit()
{
Console.Write("Press any key to quit...");
Console.ReadKey();
}
}
}
|
Chapter 10: Recursion
Length of a string
| using System;
namespace stringLength
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Length of a string - recursively");
Console.Write("Enter a string: ");
string input = Console.ReadLine();
Console.WriteLine($"The length of \"{input}\" is {GetLength(input)}");
Console.Write("Press any key to quit...");
Console.ReadKey();
}
static int GetLength(string input)
{
if (input == string.Empty)
{
return 0;
}
else
{
return GetLength(input.Substring(1)) + 1;
}
}
}
}
|
Calculate power
| using System;
namespace power
{
class Program
{
static void Main(string[] args)
{
Console.Clear();
Console.WriteLine("Calculate Power of value recursively");
Console.WriteLine(Convert.ToInt32(Power(2,8))); // 256
Console.Write("Press any key to continue...");
Console.ReadKey();
}
static int Power(int num, int exponent)
{
if (exponent == 0)
return 1;
else
return num * Power(num, exponent-1);
}
}
}
|