【自学java笔记#第十七天#】按值传递与按引用传递

package homework;

public class ParamTest 
{
    public static void main(String[] args)
    {
        System.out.println("Testing tripleValue:"); //测试能否改变基本数据类型变量的值
        double percent=10;
        System.out.println("Before:percent="+percent);
        tripleValue(percent);
        System.out.println("After:percent="+percent);
        
        System.out.println("\nTesting tripleSalary");//测试能否改变对象引用类型的值
        var harry=new Employee("Harry",50000);
        System.out.println("Before:salary="+harry.getSalary());
        tripleSalary(harry);
        System.out.println("After:salary="+harry.getSalary());
        
        System.out.println("\nTesting swap:");//测试方法对于对象引用类型的参数，是按值传递，还是按引用传递
        var a=new Employee("Alice",70000);
        var b=new Employee("Bob",60000);
        System.out.println("Before:a="+a.getName());
        System.out.println("Before:b="+b.getName());
        swap(a,b);
        System.out.println("After:a="+a.getName());
        System.out.println("After:b="+b.getName());
    }
    public static void tripleValue(double x)
    {
        x=3*x;
        System.out.println("End of method:x="+x);
    }
    public static void tripleSalary(Employee x)
    {
        x.raiseSalary(200);
        System.out.println("End of method:salary="+x.getSalary());
    }
    public static void swap(Employee x,Employee y)
    {
        Employee temp=x;
        x=y;
        y=temp;
        System.out.println("End of method:x="+x.getName());
        System.out.println("End of method:y="+y.getName());
    }

}
class Employee
{
    private String name;
    private double salary;
    public Employee(String n,double s)
    {
        name=n;
        salary=s;
    }
    public String getName()
    {
        return name;
    }
    public double getSalary()
    {
        return salary;
    }
    public void raiseSalary(double bypercent)
    {
        double raise=salary*bypercent/100;
        salary+=raise;
    }
    
    
}

Testing tripleValue:
Before:percent=10.0
End of method:x=30.0
After:percent=10.0

Testing tripleSalary
Before:salary=50000.0
End of method:salary=150000.0
After:salary=150000.0

Testing swap:
Before:a=Alice
Before:b=Bob
End of method:x=Bob
End of method:y=Alice
After:a=Alice
After:b=Bob

Date deadline=new Date();