How Java generates random numbers

First, how does Java generate random numbers?

1. Open Eclipse

2. Create a new Java project, for example, named "Suijishu" click Finish

3. Create a new class to test

4. First insert a package in the head

Enter import Java.util.Random;

5. Enter the code:

public static int Suiji = new Random (). Nextint (10);

public static void Main (string[] args) {

System.out.print (Suiji);

}

where public static int Suiji = new Random (). Nextint (10); This line is the key to generating a random number, which can generate a random number from 0 to 9

 Package Suijishu; Import Java.util.Random;  Public class suijishu{    publicstaticint Suiji =new Random (). Nextint (10 );      Public Static void Main (string[] args) {        System.out.print (Suiji);    }}

6. Test the output, you can see the generated random number

Ii. how Java implements generating non-repeating random numbers

 PackageSuijishu;ImportJava.util.Random; Public classsuijishu{ Public Static intSuiji =NewRandom (). Nextint (10);  Public Static voidMain (string[] args) {System.out.print (Suiji); }           //set several numbers           Private Static Final intLENGTH = 8; /*** This is a typical random shuffle algorithm. * The process is to select one from the alternate array into the target array, remove the selected array from the alternate array (put to the last, and narrow the selection) * Algorithm time complexity O (n) *@returnRandom 8 is a non-repeating array*/            Public Staticstring Generatenumber () {string No= ""; //initializing an alternate array               int[] Defaultnums =New int[10];  for(inti = 0; i < defaultnums.length; i++) {Defaultnums[i]=i; } Random Random=NewRandom (); int[] Nums =New int[LENGTH]; //the part length that can be selected in the default array               intcanbeused = 10; //populating the target array                for(inti = 0; i < nums.length; i++) {                   //storing randomly selected numbers in the target array                   intindex =Random.nextint (canbeused); Nums[i]=Defaultnums[index]; //throws the used number to the alternate array at the end and reduces the optional areaSwap (index, canbeused-1, defaultnums); Canbeused--; }               if(Nums.length > 0) {                    for(inti = 0; i < nums.length; i++) {No+=Nums[i]; }               }               returnNo; }           /*** Exchange Method *@paramI exchange position *@paramJ Position of Interchange *@paramnums Array*/           Private Static voidSwapintIintJint[] nums) {               inttemp =Nums[i]; Nums[i]=Nums[j]; NUMS[J]=temp; }           /*** Get 8 digits *@return            */            Public Staticstring GenerateNumber2 () {string No= ""; intNum[] =New int[8]; intc = 0;  for(inti = 0; I < 8; i++) {Num[i]=NewRandom (). Nextint (10); C=Num[i];  for(intj = 0; J < I; J + +) {                       if(Num[j] = =c) {i--;  Break; }                   }               }               if(Num.length > 0) {                    for(inti = 0; i < num.length; i++) {No+=Num[i]; }               }               returnNo; }}

The test output will find that every random number generated is different.

How Java generates random numbers