UC知道关于JAVA引用传递和值传递的题
来源：百度知道 编辑：UC知道 时间：2024/05/20 11:29:22
public class passingDemo{
public void fist(){
xObject o=new xObject();
o.x=5;
int x=5;
changeThem(x,o);
System.out.println();
System.out.println("Back in the original method");
System.out.println("The value of o.x is " + o.x);
System.out.println("But.The value of x is now " + x);
}
public void changeThem(int x,xObject o){
x=9;
o.x=9;
System.out.println("In the changThem method");
System.out.println("The value of o.x is " + o.x);
System.out.println("The value of x is now " + x);
}
public static void main(String args[]){
passingDemo myDemo=new passingDemo();
myDemo.fist();
}
class xObject{
public int x=5;
}
}
输出结果
In the changThem method
The value of o.x is 9
The value of x is now 9
Back in the original method
The v
public void fist(){
xObject o=new xObject();
o.x=5;
int x=5;
changeThem(x,o);
System.out.println();
System.out.println("Back in the original method");
System.out.println("The value of o.x is " + o.x);
System.out.println("But.The value of x is now " + x);
}
public void changeThem(int x,xObject o){
x=9;
o.x=9;
System.out.println("In the changThem method");
System.out.println("The value of o.x is " + o.x);
System.out.println("The value of x is now " + x);
}
public static void main(String args[]){
passingDemo myDemo=new passingDemo();
myDemo.fist();
}
class xObject{
public int x=5;
}
}
输出结果
In the changThem method
The value of o.x is 9
The value of x is now 9
Back in the original method
The v
1. 简单类型是按值传递的
Java 方法的参数是简单类型的时候,是按值传递的 (pass by value)。这一点我们可以通过一个简单的例子来说明：
/* 例 1 */
/**
* @(#) Test.java
* @author fancy
*/
public class Test {
public static void test(boolean test) {
test = ! test;
System.out.println("In test(boolean) : test = " + test);
}
public static void main(String[] args) {
boolean test = true;
System.out.println("Before test(boolean) : test = " + test);
test(test);
System.out.println("After test(boolean) : test = " + test);
}
}
运行结果：
Before test(boolean) : test = true
In test(boolean) : test = false
After test(boolean) : test = true
不难看出,虽然在 test(boolean) 方法中改变了传进来的参数的值,但对这个参数源变量本身并没有影响,即对 main(String[]) 方法里的 test 变量没