C array

C# Array  

Characteristics of array ：

The values stored in an array are of the same data type .

A specified element in an array is accessed through an index .

All arrays consist of contiguous memory locations .

Arrays are indexed from zero , That is, the array index starts from zero .

One dimensional array

grammar ：

Define an array ： data type [ ] Array name ;

initialization Elements in an array ：

1. data type [ ] Array name =new data type [ length ];

example ：int[] intArr = new int[5]; The length of the array 5 The content of each element is not specified , Not initialized

1. data type [ ] Array name ={ value 1, value 2,……}

example ：int[] intArr1 = { 1, 2, 3, 4 }; Initializing arrays directly , The length of the array is calculated by the compiler . And initialize

1. data type [ ] Array name =new data type [ length ] { value 1, value 2,……}

example ：int[] intArr2 = new int[3] { 5, 6,7}; Indicates the length of the array 3, And initialize

Two dimensional array ：

grammar ：

data type [ ,] Array name ;

Create a two-dimensional array and initialize it ：

data type [ ,] Array name =new data type [ m,n]{ { ,},{ ,}};

example ：int[,] intDArr = new int[2, 2] { { 1, 2 }, { 3, 4 } };

foreach Traverse

grammar ：foreach（ data type Variable name in Array name ）{ Sentence block ;}

Traversing a one-dimensional array

example ：int[] intArr1 = { 1, 2, 3, 4 };

foreach (int item in intArr1)

            {

                Console.WriteLine(item);

            }

Traversing a two-dimensional array

example ： int[,] intDArr = new int[2, 2] { { 1, 2 }, { 3, 4 } };

for (int i = 0; i < intDArr.GetLength(0); i++)

            {

                for (int j = 0; j < intDArr.GetLength(1); j++)

                {

                    Console.Write("{0}\t", intDArr[i, j]);

                }    

                Console.Write("\n"); Line break

            }

notes ：foreach Can only be used for arrays 、 String or collection data type

Type of structure

Structure type is a custom value type .

Definition grammar ：

Access modifier struct Structure name { Structural members }

Structures and classes difference ：

Structure ：

It is allowed not to use new Exemplify it

There is no default constructor

Can't inherit class

Not allowed abstract、protected as well as sealed modification

class ：

You have to use new Instantiation

There is a default construction method

Can inherit classes

Allow to use abstract、protected as well as sealed modification

Enumeration type

Enumeration type is a special value type

grammar ：

Access modifier enum Variable name ： data type { value 1, value 2,}

Enumeration class Type determines the maximum content that can be contained in an enumerated class .

data type ： It refers to the data type of the value in the enumeration . Can only be integer type . Such as byte、short、int、long etc. .

example ：  enum Week : short

        {

            SUN,    // Sunday

            MON,    // Monday

            TUE,    // Tuesday

            WED,    // Wednesday

            THU,    // Thursday

            FRI,    // Friday

            SAT,     // Saturday

            UNDEFIN,

        }

static void PrintWeek(Week week)

        {

            switch (week)

            {

                case Week.MON:// Monday

                    Console.WriteLine(" Monday ");

                    break;

                case Week.TUE:// Tuesday

                    Console.WriteLine(" Tuesday ");

                    break;

                case Week.WED:// Wednesday

                    Console.WriteLine(" Wednesday ");

                    break;

                case Week.THU:// Thursday

                    Console.WriteLine(" Thursday ");

                    break;

                case Week.FRI:// Friday

                    Console.WriteLine(" Friday ");

                    break;

                case Week.SAT:// Saturday

                    Console.WriteLine(" Saturday ");

                    break;

                case Week.SUN:// Sunday

                    Console.WriteLine(" Sunday ");

                    break;

            }

        }