C # Learning Primer First article

1.

usingSystem;usingSystem.Collections.Generic;usingsystem.ling;usingSystem.Text;usingSystem.Threading.Tasks;//namespaces, supporting class library callsnamespaceHelloWorld//Project Name{    classProgram//This is a class    {        Static voidMain (string[] args)//method (Main method)/main function        {            //program run start placeConsole.WriteLine ("Hello World");//Output DisplayConsole.readkey ();//Pause Program                    }    }}

2.

 usingSystem;usingSystem.Collections.Generic;usingsystem.ling;usingSystem.Text;usingSystem.Threading.Tasks;//namespaces, supporting class library callsnamespaceHelloWorld//Project Name{    classProgram//This is a class    {        Static voidMain (string[] args)//method (Main method)/main function        {           intnum; Num=Ten;//define an Integer variable           DoubleD//decimal type, double contains an int           floatf =3.14f;//uniity using floatD =3.14; stringstr; STR="Huang";//double quotes required           CharC//Single -characterc ='a';/ar assignment with single quotation markBOOLb//Boolean type, judging right and wrongb =true; b=false;                    Console.WriteLine (num); }    }}

3. Name of the variable:
Naming rules:
1. Must start with "letter" _ or @, do not start with a number
2 can be followed by any "letter", number, underline.
Attention:
1. The variable name you are starting with is not duplicated with keywords in the C # system.
2. In C #, casing is sensitive.
3. Duplicate definitions are not allowed for the same variable name (first thought, not rigorous)

Variable names make sense when defining variables
C # variable naming coding specification--camel nomenclature:
The first letter is lowercase and the first letter of the remaining words is capitalized.
Pascal naming conventions: Capitalize each word in the first letter
If you use abbreviations for English words, capitalize them all!

Strings that are concatenated with other types become strings.

Practice

1.

usingSystem;namespace_001lianxi{classProgram {Static voidMain (string[] args) {            stringName ="Kaka West"; stringPlace ="Fire Shadow Village"; intAge = -; stringPostbox ="[email protected]"; DoubleWage = -; //Console.WriteLine ("I call" + name+ ", I live in" + place+ ", I this year" + age+ ", my mailbox is" + postbox + ", my salary is" + wage);Console.WriteLine ("My name is {0}, this year {1} years old, home address is {2}, my mailbox is {3}, my salary is {4}", name, age, place, postbox, wage); }    }}

2.

Exchange variable values:

 using   System;  namespace   _005{ class   program { static  void  Main (string  [] args) {  int  a = 10             ;  int  b = 5              ;             A  = b- A;            b  = b- A;            A  = a + b;            Console.WriteLine (a);        Console.WriteLine (b); }    }}

3.

usingSystem;namespace_007{classProgram {Static voidMain (string[] args) {Console.WriteLine ("Please enter your name"); stringName = Console.ReadLine ();//input used to receive the userConsole.WriteLine ("Please enter your age"); stringAge =Console.ReadLine (); Console.WriteLine ("Please enter gender"); stringGender =Console.ReadLine (); Console.WriteLine ("hello: {0} sir, your age is {1}, or a handsome and pressing {2} born", name, age, Gender); }    }}

4.

C # Learning Primer First article