One dimensional array two dimensional array (sort Max insert sort)

  One .  One dimensional array

1. Definition

3W：why  what  when

1H：how

Why： Solve the problem of mass data calculation

Yes 10 Ten thousand variables ： among 3 All integers ,4 10000 double precision ,2 Ten thousand strings ,1 Ten thousand objects

An array of integers ：3 All integers

Double precision array ：4 10000 double precision

Array of strings ：2 Ten thousand strings

An array of objects ：1 Ten thousand objects

What： Definition

The dynamic array （ Show array ）： data type []  Variable name =new data type [ size ];

int[] a=new int[30000];

2、 visit

Array access ：a[i]   i： Subscript （ from 0 Start ）

assignment ：a[0]=1;

void Get()

        {

            int[] a = newint[5];// Define a have 5 Integer value of elements

            a[0] = 1;

            a[1] = 2;

            a[2] = 3;

            a[3] = 4;

            a[4] = 5;

            Console.WriteLine(a[0] + "\t" + a[3]);

        }

        void Get2()

        {

            int[] a = newint[5];

            //for (int i = 0; i <5; i++)

            //for (int i = 0; i <= 4; i++)

            for (int i = 0; i <a.Length; i++)//a.Length： Length of array

            {

                a[i] = i + 1;

            }

            Console.WriteLine(a[0] + "\t" + a[3]);

           // Unhandled exception :  System.IndexOutOfRangeException: Index out of array bounds .

        }

        staticvoid Main(string[] args)

        {

            Test15 t = newTest15();

            t.Get2();

        }

Static array （ Implicit array ）

int[] x={1,2,3,4,5};

void Get3()

        {

            // hold a Put the values of the array in reverse order b Array

            int[] a = { 1, 2, 3, 4, 5 };

            int[] b = newint[5];

            for (int i = a.Length-1; i >= 0; i--)// Loop assignment

            {

                b[4-i = a[i];//i：4 3 2 1 0

            }

            for (int i = 0; i < b.Length; i++)// Cyclic output

            {

                Console.WriteLine(b[i]);

            }

        }

Two . Two dimensional array

1. Definition

int[,] ABC = new int[3, 4] { { 4,5,8,7}, { 4, 5, 8, 7 }, { 4, 5, 8, 7},};

public enum AerType  {  // enumeration
        hj,
        bjhg,
        hja = 8,
    }
static void Main(string[] args)  {
            switch (AerType.bjhg)  {
                case AerType.hj:
                    break;
                case AerType.bjhg:
                    break;
                case AerType.hja:
                    break;
                default:
                    break;
    } }

3、 ... and . Sort

Array.Sort()

// Arrange the data in positive order

            int[] a = { 95, 74, 63, 87, 55 };

            Array.Sort(a);

            for (int i = 0; i < a.Length; i++) {    Console.WriteLine(a[i]);     }

            // Arrange the data in reverse order

            for (int i = a.Length-1; i >=0 ; i--)   {    Console.WriteLine(a[i]);     }

void Get5()

        {

            // Bubble sort

            int[] a = { 95, 74, 63, 87, 55 };

            int t;

            for (int i = 0; i < a.Length; i++)   {

                for (int j = i; j < a.Length; j++)     {

                    if (a[i] > a[j])// From small to large                   {

                        t = a[i];

                        a[i] = a[j];

                        a[j] = t;

                    }

                }

            }

            for (int i = 0; i < a.Length; i++)   {    Console.WriteLine(a[i]);  }

       }

4、 For maximum

void Get6()

        {

            // Get the highest score

            int[] a = { 45, 74, 63, 87, 55 };

            //1、 Suppose a number in the array is the highest score

            int max = a[2];

            //2、 Circular array , Find out the ratio max Big points , Assign this score to max

            for (int i = 0; i < a.Length; i++)   {    if (a[i] > max)   {    max = a[i];   }    }

            Console.WriteLine(max);

        }

5、 ... and . Insertion sort

There is a group of students' achievements {99,85,82,63, 60}, To increase the performance of a student , Insert it into the grade sequence , And keep descending

65

analysis ：

1. Find a number smaller than this data for the first time , This number is where the data is to be inserted i（ Judge this data ）, Exit the loop when found
2. from i Position of backward , Move the following data backward in turn
3. hold i This position is assigned to the data to be inserted

void Insert()// Insertion sort

        {

            int[] a = { 99, 85, 82, 63, 60,0 };

            int b=65,index=0;

            for (int i = 0; i < a.Length; i++)   {

                if (b >= a[i])    {     index = i;     break;    }

            }

            //99,85,82,63, 60   []

            //99,85,82,[i] ,63, 60

            //99,85,82,[index] ,63(i), 60

            for (int i = a.Length - 1; i >= index + 1; i--)  {     a[i] = a[i - 1];     }

            a[index] = b;

            for (int i = 0; i < a.Length; i++)  {    Console.WriteLine(a[i]);   }

        }