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MbuguaCaleb/csharp_fundamentals.cs

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Fundamentals of the C# Programming Language.
Raw
csharp_fundamentals.cs
#Strings and String Methods.
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//we put all the code we want our program to execute at the Main method
string name= "Caleb is Born Again!";
//length of the string returned.
Console.WriteLine(name.Length);
Console.WriteLine(name.ToUpper());
Console.WriteLine(name.ToLower());
Console.WriteLine(name.Contains("Born"));
Console.WriteLine(name[0]);
Console.WriteLine(name.IndexOf('C'));
Console.WriteLine(name.Substring(9));
Console.WriteLine(name.Substring(9, 3));
Console.ReadLine();
}
}
}
##Numbers
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//we put all the code we want our program to execute at the Main method
int num = 6;
//Console.WriteLine(num++);
Console.WriteLine(num);
Console.WriteLine(++num);
//Numbers Methods
Console.WriteLine(Math.Abs(-30));
Console.WriteLine(Math.Pow(4.5, 2));
Console.WriteLine(Math.Sqrt(36));
Console.WriteLine(Math.Max(4, 99));
Console.WriteLine(Math.Round(4.7));
//Console.WriteLine(5 * 5);
//Console.WriteLine(5 % 2);
//Console.WriteLine(4+2*3);
//Console.WriteLine((4+2)*3);
//Integer Operations always return integers
//Console.WriteLine(5 / 2);
//This would be the correct way for the above
//Console.WriteLine(5 / 2.0);
Console.ReadLine();
}
}
}
##Getting User Input
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//write does not progress our cursor to the next page
Console.Write("Hello, What is your name ? ");
string name = Console.ReadLine();
Console.Write("Hello, What is your age ? ");
string age = Console.ReadLine();
Console.WriteLine("Congrats! Your name is" + name +"You are "+ age + "Years Old" );
Console.ReadLine();
}
}
}
##Building a Basic Calculator
##Convert String to an Integer
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//Converting a String to a Number
int a = Convert.ToInt32("45");
Console.WriteLine(a + 5);
Console.ReadLine();
}
}
}
##The Calculator
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//Converting a String to a Number
//C# is very sensitive
//If you declare an integer as your type there is no way that a double will work.
Console.Write("Enter a number: ");
double a = Convert.ToDouble(Console.ReadLine());
Console.Write("Enter another number");
double b = Convert.ToDouble(Console.ReadLine());
Console.WriteLine(a + b);
Console.ReadLine();
}
}
}
##Simple MadLips Game
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
string color, pluralNoun, celebrity;
Console.Write("Enter a Color: ");
color = Console.ReadLine();
Console.Write("Enter a pluralNoun:");
pluralNoun = Console.ReadLine();
Console.Write("Enter a Celebrity:");
celebrity = Console.ReadLine();
Console.WriteLine("Roses are" + color);
Console.WriteLine(pluralNoun+ "are Blue");
Console.WriteLine("I love " + celebrity);
Console.ReadLine();
}
}
}
##Arrays
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//Array is a data structure that enables us to hold mutiple pieces of information in a container
int[] luckyNumbers = { 1,2,3,4,6,7,8,9,3};
luckyNumbers[1] = 20;
//All the pieces of information need to be of the same type
//When i am makig a dynamic array where i dont know exacly what values will be there
//ido as below
//i must tell c# what the size of my array will be
string[] friends = new string[5];
friends[0] = "Justin";
friends[1] = "Brian";
Console.WriteLine(luckyNumbers[1]);
Console.WriteLine(friends[1]);
Console.ReadLine();
}
}
}
##Methods Intro
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//notice that am calling my methods from the main function.
SayHi();
Response("Good",10);
Response("Better",15);
Response("Best",20);
Console.ReadLine();
}
static void SayHi()
{
//Only characters in C# can be enclosed in single quotes but not strings
Console.WriteLine("Caleb Says Hi!");
}
static void Response(string response,int age)
{
Console.WriteLine("I am doing" + response+ "I am "+ age + "Years Old");
}
}
}
##Methods Return Statement
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
int cubedTwo = cube(2);
Console.WriteLine(cubedTwo);
Console.WriteLine(cube(20));
Console.ReadLine();
}
static int cube(int num)
{
int result = num * num * num;
return result;
}
}
}
##Beginning if Statements
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
bool isMale = true;
bool isTall = true;
//Both Conditions have to be True
if (isMale && isTall)
{
Console.WriteLine("You are a Tall Male");
}
if(!isMale && isTall)
{
Console.WriteLine("You are not male but you are tall");
}
else if(isMale && !isTall)
{
Console.WriteLine("You are Male and you are Not tall");
}
else
{
Console.WriteLine("You are eith not male or tall or both");
}
//Only one condition has to be True
if (isMale || isTall)
{
Console.WriteLine("You are a Tall Male");
}
else
{
Console.WriteLine("You are eith not male or tall or both");
}
Console.ReadLine();
}
}
}
##Comparison Operators
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
int max = GetMax(11, 10,223);
Console.WriteLine(max);
Console.ReadLine();
}
static int GetMax(int num1 ,int num2,int num3)
{
int result;
/*
Comparison operators
= (Assignemt)
== (Comparison)
===(Also checks the Type)
!= (Evalates not Equal to)
> Greater than < Less than
>=
<=
*/
if (num1>=num2 && num1>=num3)
{
result = num1;
}
else if(num2>=num1 && num2 >= num3)
{
result = num2;
}
else
{
result = num3;
}
return result;
}
}
}
##More Complex Calculator
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
Console.Write("Enter a Number:");
double num1 = Convert.ToDouble(Console.ReadLine());
Console.Write("Enter an Operator");
string op = Console.ReadLine();
Console.Write("Enter a Second Number:");
double num2 = Convert.ToDouble(Console.ReadLine());
if( op == "+")
{
Console.WriteLine(num1 + num2);
}
else if (op == "-")
{
Console.WriteLine(num1 - num2);
}
else if (op == "/")
{
Console.WriteLine(num1 / num2);
}
else if (op == "*")
{
Console.WriteLine(num1 * num2);
}
else
{
Console.WriteLine("Invalid Operand!!!");
}
Console.ReadLine();
}
}
}
##Switch Statements
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
Console.Write("kindly key in the Day:");
int day = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(GetDay(day));
Console.ReadLine();
}
//functions must always be executed outside of my main
//A switch case is a special type of if statement that can evaluate Mutiple Conditions
static string GetDay(int dayNum)
{
string dayName;
switch (dayNum)
{
case 0:
dayName = "Sunday";
break;
case 1:
dayName = "Monday";
break;
case 2:
dayName = "Tuesday";
break;
case 3:
dayName = "Wednesday";
break;
case 4:
dayName = "Thursday";
break;
case 5:
dayName = "Friday";
break;
case 6:
dayName = "Saturday";
break;
default:
dayName = "Invalid Day provided";
break;
}
return dayName;
}
}
}
##While and Do While Loops
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//Loops over a certain condition as long as it is True
int index = 1;
while(index <= 5)
{
Console.WriteLine(index);
index++;
}
//DO While loop
//It executes the code in the loop at least once before checking the condition
int indexTwo = 6;
do
{
Console.WriteLine(indexTwo);
indexTwo++;
} while (indexTwo <= 5);
Console.ReadLine();
}
}
}
##Loops Game;
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//Loops over a certain condition as long as it is True
int index = 1;
while(index <= 5)
{
Console.WriteLine(index);
index++;
}
//DO While loop
//It executes the code in the loop at least once before checking the condition
int indexTwo = 6;
do
{
Console.WriteLine(indexTwo);
indexTwo++;
} while (indexTwo <= 5);
Console.ReadLine();
}
}
}
##While and Do While Loop Game
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
string secretWord = "Caleb";
string guess = "";
/*
while (guess != secretWord)
{
Console.WriteLine("Enter the Secret Word!");
guess = Console.ReadLine();
}
Console.WriteLine("You Win!!");
*/
//Using Do while
do
{
Console.WriteLine("Enter the Secret Word!");
guess = Console.ReadLine();
} while (guess != secretWord);
Console.WriteLine("Cograts!! You win");
Console.ReadLine();
}
}
}
##Advanced While Loop Game
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
string secretWord = "Caleb";
string guess = "";
int guessCount =0;
int guessLimit = 3;
bool limitsExhasted = false;
while (guess != secretWord && !limitsExhasted)
{
if(guessCount < guessLimit)
{
Console.WriteLine("Enter the Secret Word!");
guess = Console.ReadLine();
guessCount++;
}
else
{
limitsExhasted = true;
}
}
if (limitsExhasted)
{
Console.WriteLine("Ooops!Your chances got exhasisted!!");
}
else
{
Console.WriteLine("You Win!!");
}
Console.ReadLine();
}
}
}
##For Loop
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
for(int i=0; i<=5; i++)
{
Console.WriteLine(i);
}
int [] gradesArray = { 20,21,93,33,55,66,67};
for(int i =0; i<gradesArray.Length; i++)
{
Console.WriteLine(gradesArray[i]);
}
Console.ReadLine();
}
}
}
##Exponential For Loop
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine(PowerLoop(3, 5));
Console.ReadLine();
}
//remeber functions convetions
static int PowerLoop(int baseNum, int powerNum)
{
int result = 1;
for( int i =0; i< powerNum; i++ )
{
result = result * baseNum;
}
return result;
}
}
}
##2 Dimensional Arrays
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//Declaration
int[,] twoDimensionalArray =
{
{1,2 },
{3,4 },
{5,6 },
{7,8 }
};
//Dymanic declaration
int[,] dynamicDeclaration = new int[2, 3];
Console.WriteLine(twoDimensionalArray[1, 1]);
Console.ReadLine();
}
}
}
##Comments
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
//single line comments
/*
* Multi Line Comments.
*
*/
Console.ReadLine();
}
}
}
##Execption Handling
1.General Try Catch Exception
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
try
{
Console.Write("Enter a Number:");
int num1 = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter a Second Number:");
int num2 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(num1 / num2);
}
catch(Exception e)
{
Console.WriteLine(e.Message);
}
Console.ReadLine();
}
}
}
2.More Ellaborate Exceptions
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
try
{
Console.Write("Enter a Number:");
int num1 = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter a Second Number:");
int num2 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(num1 / num2);
}
catch(DivideByZeroException e)
{
Console.WriteLine(e.Message);
}
catch(FormatException e)
{
Console.WriteLine(e.Message);
}
Console.ReadLine();
}
}
}
3.Adding finally that is going to Execute no matter what.
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
try
{
Console.Write("Enter a Number:");
int num1 = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter a Second Number:");
int num2 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(num1 / num2);
}
catch(DivideByZeroException e)
{
Console.WriteLine(e.Message);
}
catch(FormatException e)
{
Console.WriteLine(e.Message);
}
finally
{
}
Console.ReadLine();
}
}
}
4.Classes Constructor Method.
##Class
using System;
using System.Collections.Generic;
using System.Text;
namespace csharp_one
{
//Classes are Le New Datatypes which we create and which Model Real World Entities.
class Book
{
//class attributes.They define the blue print of my Classes.
//Classes gives us more of the templates of an object
public string title;
public string author;
public int pages;
//Constuctor is a Method that gets called when we create an object of that class
//It is the Method that is given the name of the class
public Book(string aTitle, string aAuthor,int aPages)
{
title = aTitle;
author = aAuthor;
pages = aPages;
}
}
}
##Calling Class
using System;
namespace csharp_one
{
class Program
{
static void Main(string[] args)
{
Book book1 = new Book("Deutronomy", "Moses", 200);
Book book2= new Book("Genesis", "Moses", 200);
//Updating class Attributes.
book2.title = "Leviticus";
Console.WriteLine(book2.title);
Console.ReadLine();
}
}
}
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