Language Basics + data type + operators

First, C # Language Foundation

New project: file → new → project →Visual C #(default . NET Framework 4.5) → console application

1. Project structure

(1) project suffix

. config --configuration file (storage configuration parameter file)

. csproj --project file (management file entry)

. sln -Solution files (Manage projects)

. CS --(program code)

(2) Four elements of the function: name, input, output, processing

(3) main function, input statement, output statement

Useing --Library referenced by the program

Namespace consoleapplication3--namespace

Class program--Classes

static void Main (string[] args)--method

(4) shortcut keys

alt+→ prompt, click Start or Ctrl+f5 when you need to execute the program

Ctrl+e,c Comment Bank ctrl+e,c uncomment the bank

(5) Comment method

A// comment line

/**/ Comment section

put it on the function and annotate the function.

Ii. Types of data

1. Basic data type (value type)

int integer type Int32 is 4b in size (range:-2^31 to 2^31-1)

Long Large integer type Int64 is 8b in size (range:-2^62 to 2^62-1 )

double dual-precision floating-point decimal size 8b

Decimal Single-precision floating-point decimal fraction of 16b size

String literal type

2. Reference type

(1) String type

String is equivalent to a character type, long, and is defined by double quotation marks

such as:string a = "Hello."; String B = "15";

(2) array type

Int a = 11; Double b = 12.5;

3. Basic type Conversion

(1) automatic conversion (implicit conversion)-when converting from a value type to a reference type

Method: Int a = 5;

String B = a.tostring ();

(2) casts (explicit conversions)-when converting from a reference type to a value type, or from a floating-point type to an orthopedic

when you convert from a reference type to a value type, you must reference the data element in the type, which can be converted to a value type in the capacity range, or you cannot go

method One: with ()

int A;

Double b = 12.3;

A = (int) b;

Method Two: with Convert

Int A;  float C; Doulbe b=12.3;

A=convert.toint32 (b); C=convert. ToSingle (b);

method Three: with Parse

Int A; Double b=12.3;

A=int. Parse (b);

Summary:b= (ing) A; equivalent to B=int. Parse (a); equivalent to B=convert. ToInt32 (a);

Third, operator

arithmetic

+ + + + +- - minus * multiply / divide % take more + plus - minus

Relationship

> Greater than < less than >= greater than or equal to <= less than equals = = equals ! = does not equal

Logic

&& with (and) | | or ! Non (note: highest priority!) )

Conditional Operators

? : If it is

Assign Value

=  +=  -=  *=  /=  %=

For example:x+=5 is x=x+5

Example:

Console.Write (" Please enter the number within the range:");

String s = console.readline ();

Int num = Convert.ToInt32 (s);

Console.WriteLine (" number is a multiple of 7" + (num%7==0));

Console.WriteLine (" Number 10 digits is a multiple of 7" + (num/10==7));

Console.WriteLine (" digit single digit is a multiple of 7" + (num%10==7));

Language Basics + data type + operators