From scratch learn Java-9. description object, learn java-9 object

From scratch learn Java-9. description object, learn java-9 object

1. Create variables for classes or objects;
2. Use methods of objects and classes;
3. Call the method and return a value;
4. Create a constructor;
5. Pass parameters to the method;
6. Use this to reference objects;
7. Create a new object.

Program VirusLab: test the functions of the Virus class

 1 package com.jsample; 2  3 public class VirusLab { 4     public static void main(String[] args){ 5         int numViruses = Integer.parseInt(args[0]); 6         if (numViruses > 0){ 7             Virus[] virii = new Virus[numViruses]; 8             for(int i = 0; i < numViruses; i++){ 9                 virii[i] = new Virus();10             }11             System.out.println("There are " + Virus.getVirusCount()12                 + " viruses.");13         }14     }15 }

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Input: 19000000
Output:

There are 19000000 viruses.

Virus: used to simulate a Virus attribute in a very rough way.

1 package com. jsample; 2 3 public class Virus {4 static int virusCount = 0; // class Object, counting the number of Virus class objects 5 6 private int newSeconds; // breeding speed 7 8 public Virus () {9 virusCount ++; // Method for auto-incrementing new Virus 10} 11 12 public int getNewSeconds () {// return the value of newSeconds 13 return newSeconds; 14} 15 16 public void setNewSeconds (int newValue) {// when the new value is between 60 and, set newSeconds to the provided value 17 if (newValue >=60 & newValue <= 100) 18 newSeconds = newValue; 19} 20 21 static int getVirusCount () {22 return virusCount; 23} 24}

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Program Change: accepts a string parameter and converts it to a float variable, a Float object, and an int variable.

 1 package com.jsample; 2  3 public class Change { 4     public static void main(String[] args){ 5         System.out.println(); 6         System.out.println(args[0]); 7         float a = Float.parseFloat(args[0]); 8         System.out.println(a); 9         Float b = a;10         System.out.println(b);11         int c = (int)a;12         System.out.println(c);13     }14 }

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Input: 190.52

Output:

190.52
190.52
190.52
190