C # Basic Knowledge Summary

After the basic video, found that some of the most basic knowledge points also mastered enough, summarized as follows:

1) placeholder

 1  string  name =  "  Zhang San  "   2  int  age = 28   3  decimal  salary = 7600.33m  ;  4  int  number = 1000   5   "  My name is {0}, this year {2} years old, my salary is {1} yuan", name,age,salary,number);  

-{0}, {1}, {2} is a placeholder, followed by the parameter substitution placeholder

-parameters that can have more than a placeholder, such as number
-placeholders can appear in a non-sequential order

2) escape characters in a string
When we need to enter special characters in a string, such as line breaks, half-width quotes, backspace

1 Console.WriteLine ("");

-The transfer character is a character that is made up of a \+ of a letter

-There are two meanings to precede the string with an @ symbol

• Escape character no longer escaped
• To make a string line wrap
• Use two double quotes to represent a double quote

3) Variable naming rules
-Camel First Letter lowercase, the remaining words capitalized in the first letter
-Pascal First letter capitalized, the remaining words capitalized in the first letter

4) Convert Usage

1 "  - " ; 2 int isore = Convert.ToInt32 (Strcor);

All types can be turned into string

5) Else forever and the nearest if pairing

1 intAge = the;2 CharSex ='F';3  4 if(Age <Ten)5    if(Sex = ='F')    6Console.WriteLine ("A");7    Else8Console.WriteLine ("B");9Console.readkey ();

else is paired with the nearest if (sex = = ' f '), not with if (AGE<10).

6) Multiple Case statements

1 Switch(month)2 {3      Case 1:4      Case 3:5      Case 5:6Console.WriteLine (" Days");7 Break ;8     ......9}

7) Do While

1 string " y " ; 2  Do 3 {4     Console.WriteLine ("Again"); 5  while " N ");

8) When an exception occurs in try, the code following the try exception is no longer executed, immediately jumps into the catch execution

1 Try 2 {3     intScore =Convert.ToInt32 (Console.ReadLine ());4Console.WriteLine ("In try");5 }6 Catch7 {8Console.WriteLine ("In catch");9 }TenConsole.WriteLine (" Over");

9) Enumeration: Define a type and specify a value of this type when defining this type

1 enum MyType {value1, value2, Value3 ...}

-enumerations are defined at the same level as class definitions, so that classes can use enumerations under the same namespace
- enum types can be converted to int types
-Ensure data consistency
-No need to memorize data values

The role of the enumeration:

- Limit the assignment of the user, only select from the values enumerated
-No need to call memory value, just select value

1 enumGender2 {male,3 female4 }5 6 Gender sex;7Sex =Gender.male8 9 Switch(Sex)Ten { One      CaseGender.male: AConsole.WriteLine ("male"); - Break ; -      CaseGender.female: theConsole.WriteLine ("female"); - Break ; - } -  + strings =console.readline (); - Try + { A  　　 sex = (Gender) (Enum.parse (typeof (Gender), s)); at } - Catch - { -Console.WriteLine ("the gender you entered is wrong"); -}

-male = 1
-female = 2 (default + 1)
-Conversion of strings and enumerations sex = (Gender) (Enum.parse (typeof (Gender), s));

C # Basic Knowledge Summary