static void Main(string[] args)
{
// C# is a statically types language which means once you declare a variable you need to specify its type
// and that type cannot chnage during the lifetime of that variable
Console.WriteLine("Test Yash");
// Variables and Constants
// case sensitive
// Identifiers -
// 1. Cannot start with a number eg: 1Route; eg: oneRoute
// 2. Cannot include a whitespace eg: first Name; eg: firstName
// 3. Cannot be a reserve keyword eg: int; eg: @int
// 4. Use meaning full names eg: fn; eg; firstName
// data type can be replaced with var and .net complier with map the data type to c#
// default type is integer for integral numbers
// TO delete a line -> Ctrl + X
var num1 = 3;
var booleanTest = true;
int number;
int Number = 1;
const float Pi = 3.14f;
const double Pii = 3.14; // default data type for decimal numbers in c#
const decimal Piii = 3.14m;
char character = 'A';
string name = "Yash";
bool isWorking = true;
// Console.WriteLine() -> shortcut - type cw and two times tab button
// Naming Conventions - Popular
// 1. Camel Case = firstName -> mostly used
// 2. Pascal Case = FirstName
// 3. Hungaration Notation = strFirstName -> not used in c# mostly
// For Local Variables -> Use Camel case eg: number
// For Constants -> Use Pascal case eg: Pi
// ************************************************************************************************ //
// Primitive Types
// byte, short, int, long, float, double, decimal, char, bool
// They all are strucutres in .net framework
// Non-Primitive Types
// String, Array, Enum, Class
// They all are classes in .net framework
// **************************************** //
// OverFlowing //
// **************************************** //
byte num = 255;
num++;
Console.WriteLine(num);
checked
{
byte num2 = 255;
num1++;
Console.WriteLine(num1);
}
// **************************************** //
// Scope //
// **************************************** //
// Where a varaibale/constant has meaning or accessible
{
byte a = 1;
{
byte b = 2;
{
byte c = 3;
}
}
}
// a is accessible in the entire block and the child blocks b & c
// b is accessible in the entire block and the child block c
// c is accessible only in the block c
// **************************************** //
// Variables & Constants //
// **************************************** //
// Place Holders - String Format
Console.WriteLine("Place Holders");
Console.WriteLine("{0} {1}", byte.MinValue, byte.MaxValue);
Console.WriteLine("{0} {1}", float.MinValue, float.MaxValue);
const float p = 3.14f;
// **************************************** //
// Type Conersion //
// **************************************** //
// 1. Implcit Type Coversion
byte b1 = 8;
int i = b1;
float f = i;
Console.WriteLine(Convert.ToString(b1, 2));
Console.WriteLine(Convert.ToString(1, 2));
Console.WriteLine(BitConverter.GetBytes(f)); // Explore how to generate float binary code
// byte b2 = i; this gives error
// 2. Explicit Type Conversion (casting)
float f1 = 1.0f;
int i1 = (int)f1;
// 3. Conversion between non-compatible types
string s = "1";
int i3 = Convert.ToInt32(s);
int i4 = int.Parse(s);
// Convert ->
// 1. ToByte()
// 2. ToInt16() - short
// 3. ToInt32() - int
// 4. ToInt64() - long
try
{
var num4 = "1234";
byte b3 = Convert.ToByte(num4);
Console.WriteLine(b3);
}
catch (Exception e)
{
Console.WriteLine("The number could not converted to a byte " + e.Message);
}
try
{
string str = "tru1e";
bool bool1 = Convert.ToBoolean(str);
Console.WriteLine(bool1);
}
catch (Exception)
{
Console.WriteLine("The string cannot be converted to a boolean");
}
// **************************************** //
// Operators //
// **************************************** //
// 5 types of operators
// 1. Arithmatic (+, -, *, /, %, ++, --), Postfix and prefix
// 2. Comparison (==, !=, >, >=, <, <=)
// 3. Assignment ( =, +=, -=, *=, /=)
// 4. Logical ( &&, ||, !)
// 5. Bitwise (&, |)
int a1 = 1;
int b5 = ++a1;
int b4 = a1++;
Console.WriteLine("{0}, {1}, {2}", b5, b4, a1); // 2,2,3
// **************************************** //
// Logical Operators //
// **************************************** //
int a6 = 10;
int b6 = 3;
Console.WriteLine(a6 + b6);
Console.WriteLine(a6 - b6);
Console.WriteLine(a6 * b6);
Console.WriteLine(a6 / b6);
Console.WriteLine((float)a6 / (float)b6);
Console.WriteLine(a6 % b6);
Console.WriteLine(a6 == b6);
Console.WriteLine(a6 != b6);
Console.WriteLine(a6 > b6);
Console.WriteLine(a6 < b6);
int c6 = 4;
Console.WriteLine(c6 > b6 && b6 < a6);
// ************************************************************************************************ //
// Non-Primitive Types
// ************************************************************************************************ //
// 1. Classes
// 2. Structures
// 3. Arrays
// 4. Strings
// 5. Enums
// Reference types vs Value Types -> Memory management of different types in c#
// Classes
// An object is an instance of a class
// Access Modifier -> determines who can access the class
// public -> class acceseble in anywhere in the application
// static Modifier -> Method is declared as static, now the method can be accessed directly
// using the class name without creating an object. We cannot access static members from objects
// Only one created in memory (same reference always - singleton)
Person yash = new Person();
yash.firstName = "Yashwanth";
yash.lastName = "Iddibani";
yash.Introduce();
Calculator cal = new Calculator();
int result = cal.Add(2, 3);
Console.WriteLine("Sum of two Numbers: " + result);
// Structs - Similar to classes,
// Arrays - A datastructure to store a collection of variables of the same type
// it is an object
// zero index based
var numArray = new int[3] {
4, 5, 6
};
numArray[0] = 1;
numArray[1] = 2;
numArray[2] = 3;
var flags = new bool[3];
flags[0] = true;
Console.WriteLine(flags[0]);
Console.WriteLine(flags[1]);
Console.WriteLine(flags[2]);
var names = new String[3] {
"Jack", "John", "Mary"
};
// Strings - A sequence of characters eg:- "Hello World"
string str1 = "Yash";
string str2 = "Yashwanth" + " " + "Iddibani";
string str3 = string.Format("{0} {1}", "Yaswanth", "Iddibani");
string list = string.Join(",", numArray);
char firstChar = str1[0];
Console.WriteLine(str3);
Console.WriteLine(list);
// strings are immutable - Once you create them, you cannot change them
str1 = "Yaashwanth";
// str1[0] = "A";
// Escapre Characters -> {\n, \t, \\ (BackSlash), \*, \" }
// Varbatim strings
string path = "D:\\VisualStudioProjects\\CSharp";
string path1 = @"D:\VisualStudioProjects\CSharp";
var firstName1 = "Yash";
string lastName1 = "Iddibani";
// string vs String
// c# data type and .net data type.. String needs to be imported
// Integrated with Git
}
static void Main(string[] args)
{
bool endApp = false;
Console.WriteLine("Console Calculator in C#\r");
Console.WriteLine("------------------------\n");
while (!endApp)
{
string numInput1 = "";
string numInput2 = "";
double result = 0;
Console.Write("Введите первое число: ");
numInput1 = Console.ReadLine();
double cleanNum1 = 0;
while (!double.TryParse(numInput1, out cleanNum1))
{
Console.Write("Ошибка ввода ");
numInput1 = Console.ReadLine();
}
Console.Write("Введите второе число ");
numInput2 = Console.ReadLine();
double cleanNum2 = 0;
while (!double.TryParse(numInput2, out cleanNum2))
{
Console.Write("Ошибка ввода");
numInput2 = Console.ReadLine();
}
Console.WriteLine("Выберите действие:");
Console.WriteLine("\ta - Добавить");
Console.WriteLine("\ts - Вычесть");
Console.WriteLine("\tm - Умножить");
Console.WriteLine("\td - Делить");
Console.Write("Выберите опцию ");
string op = Console.ReadLine();
try
{
result = Calculator.DoOperation(cleanNum1, cleanNum2, op);
if (double.IsNaN(result))
{
Console.WriteLine("Математическая ошибка.\n");
}
else
{
Console.WriteLine("Результат:" + result);
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
Console.WriteLine("------------------------\n");
Console.Write("Нажмите q для закрытия приложения ");
if (Console.ReadLine() == "q")
{
endApp = true;
}
Console.WriteLine("\n");
}
return;
}
