C # language Basics

I. INPUT and OUTPUT statements

The main input and output statements of the main function are:

Console.Write (); Output statement, do not wrap line

Console.WriteLine (); Output statement, wrap line

Console.read (); Input statement, does not wrap line

Console.ReadLine (); Input statement, wrap line

C # statements are sensitive to the case of English letters, and you must pay attention to the case of letters when writing code. After writing each sentence of the code, you must add ";" to indicate the end of the sentence. Also, when writing code, all punctuation must be entered in English input state, otherwise, the input code will be error. When you enter the program, you can Press "alt+→", pop-up program statement prompts, to help us complete the writing of the statement. The "+" in the input and output statements is not a representation of the addition operation, but rather a concatenation of the contents before and after "+".

Note There are several ways to do this:

Comment Line

/* * * comment on an area

Put it on the function and annotate the function.

You can also annotate a selected piece of text using the comment Select Line button or its shortcut key on the toolbar in the Visual Studio software. Ctrl+e,c.

In this part of the study, I did a little exercise:

get to the user's name, age and work unit, and complete the "I call * * *, this year * * * years old, work in * * *. "In a word.

Console.WriteLine ("Please enter your name:");

String a = Console.ReadLine ();

Console.WriteLine ("Please enter your Age:");

String B = Console.ReadLine ();

Console.WriteLine ("Please enter your work unit:");

String c = Console.ReadLine ();

Console.WriteLine ("I Call" +a+ ", this year" +b+ "years old, in the" +c+ "work. ");

Console.WriteLine ("I call {0}, this year {1} years old, working at {2}.") ", a,b,c);//use a placeholder to take up the empty space first

Console.ReadLine ();

Ii. Types of data

		C # language	. NET type (Common language)	Size (bytes)	Value Range
Basic data types (value type)	Integral type	Byte	Byte	1	0-255
		Short	Int16	2
		Int	Int32	4	-231~231
		Long	Int64	8
	Floating point Type	Float	Single	4
		Double	Double	8
		Decimal	Decimal	16
	Character type	Char	Char	2	Any character
	Boolean type	bool	Boolean	1	True or False
	Date Time	Datatime
	Enum type	Enum
	Structure type	struct
Reference class	String type	String	String		Character sequences

There are three main ways to perform basic type conversions:

1. Use ()

2. Use Convert

3. Using the Parse

Example:

int A;
float B = 3.14;
A = (int) b; With ()
A = Convert.ToInt32 (b); With convert
a = Int. Parse (B.tostring ()); The value to be placed with parse is a string type

In this part of the study, I do the small exercise is:

Q: What time is the old Wolf Wolf?

If the morning, the direct output time and add am, if the afternoon, the actual time minus 12 plus PM (12-hour clock to represent the time)

Console.Write ("What time is the wolf old Wolf?" ");

int time = Int.   Parse (Console.ReadLine ()); ReadLine command default data type is string, cast to int type with parse

String ap = time > 12? (time-12) + "PM": time+ "AM";

Console.WriteLine (AP);

Console.ReadLine ();

Third, operator

Classification	Symbol	Explain	Priority level
Count	++  --	Gaga minus minus	From high to low, that is, the execution order is from top to bottom. (highest precedence of parentheses)
	* / %	Multiplication to take the remainder
	+  -	Add and Subtract
Relationship	> < >= <=	Greater than or equal to less than or equal to
	= =! =	equals Not equal to
	&&	With (and)
	||	Or
	！	Non ( Note: Priority at the top level of this table )
Conditional operators	？ ：	The only ternary operator if
Assign value	=  +=  -=  *=  /=  %=	such as: X-=4. That is x=x-4

In an assignment operation, the first + + is performed +1 and then assigned, and the next + + executes the assignment before performing the +1 operation.

When a new value of two data classes is calculated, the type with the largest range is automatically taken.

In this section of the study, I completed the small exercise is:

determine if an integer within 100 is a multiple of 7, or does it contain 7?

Console.Write ("Please enter an integer within 100:");
int num = Int. Parse (Console.ReadLine ());
Console.WriteLine ("Is it a multiple of 7?") "+ (num%7==0));
Console.WriteLine ("is the single digit 7?") "+ (num%10==7));
Console.WriteLine ("is the 10-digit number 7?") "+ (num/10==7));
Console.ReadLine ();

C # language Basics