JAVA basic concepts (c)

JAVA parameter and return type of the method

• Into the reference method

  • Basic data types

  • Reference data types

  Modifier return type method name (parameter type parameter name, parameter type parameter name ... ) { 
  // method body 
  return 
  }

• Method return types

  • the specific type of return xxx

  • If you do not return, the method returns the type to write void

  Modifier void ⽅ method name ( parameter type parameter name, parameter type parameter name ...) { 
  // ⽅ method thereof 
  }

example

1 package study2day;public class Student1 {    
2     private int age;    
3     public void setAge(int age){        
4         this.age =age;    
5     }    
6     public int getAge(){        
7         return  age;    
8     }
9 }

Note: The first one is the reference code

 1 package study2day;
 2 ​
 3 public class ParamTest {
 4     public static void main(String [] args){
 5         ParamTest.calculate("5000",2000);
 6         Student1 a = new Student1();
 7         a.setAge(10);
 8         System.out.println("操作前="+a.getAge());
 9         changeAge(a);
10         System.out.println("操作后="+a.getAge());
11     }
12 ​
13     public static void calculate(String numbera,int numberb){
14         System.out.println("numbera ="+numbera);
15         System.out.println("numberb ="+numberb);
16     }
17     public static void changeAge(Student1 hx){
18         hx.setAge(27);
19     }
20 }