JAVA中的方法---练习

 

方法:实现一定的功能的代码的集合

方法名字:首字母小写,后面单词的首字母大写

java中方法的定义:

return的作用:方法的返回,将计算结果返回或者结束方法

修饰符   返回值类型   方法名(参数列表){

方法的功能主体

循环、判断、变量、比较、运算

Return 返回值;

}

JAVA方法实例

public class MethcdDemo{ 
public static VOICI main args) { 
System. out . ( 
*area) ; 
publ±c stat±c Int h, w) { 
return a ; 
D : MethodDemo. java 
MethodDemo

方法调用内存图

public static void main (String[] args) { 
int area = getArea ( 
5,6) 
System. out . println ( 
. "+area) ; 
public static int getArea (int w, int h) { 
//int area 
return w * h; 
ma i 
ma i ,fiEgetArea fiÉä-R-30 
getAreaO w,h 
return 30; 
main 
30 
int area = getArea( 5, 6); 
sop (area); 
MethodDemo.class 
main O 
getAreaO

方法的定义与调用问题实例

-EE(L) 
8 
— public class MethcdDemo I { 
public static void main (SC ling [ ] 
printRecC ( 
LD,2D) 
System. ouc . print In (geCA%W ( 
D: MethodDemo_1. java 
D: MethodDemo_1 
args) { 
b, int 
public static int getAw(inC a, int 
return (a+b+c) / 3 
public static void prinCRecC (int m, int 
for (int i=C' { 
for (int ; { 
System. out . print 
System. ouc . prinCIn ( ) ;

方法的重载问题:

在同一个类中,允许出现同名的方法,只要方法的参数列表不同即可,这就是方法的重载

Jilt— 
— public class MethcdCveILoadDemo{ 
public static void main (SC Iing[] args) { 
System. ouc . print In (geCSum(2 , 3)) ; 
public static int getSum(inC a, int b) { 
System. out ( 
return a+b ; 
public static int getSum(inC a, int b, int 
0 int $ % : " 
System. out ( " 
return a+Nc ; 
public static dcuble getSum(dcubIe a, 
System. out ( 
return a+b ; 
D: MethodOverLoadDemo. java 
D: MethodOverLoadDemo 
int-S_ä: 
D: MethodOverLoadDemo. java 
D: MethodOverLoadDemo 
int-%2:

 

 

方法参数的不同类型

1、方法参数为基本类型:不返回值

-public class MethodDemo 3 { 
public static void main (String[] 
args) { 
Int a = 
1, 
int b = 
2 
change (a ; 
System. out . println (a) ; 
System. out . println (b) ; 
//1 
public static void change (int a, int b) { 
a = a+b; 
b = b+a;

2、方法参数为引用数据类型:传递的是内存的地址,方法中数据改变会引起调用结果的改变

6 
8 
9 
20 
21 
22 
23 
24 
25 
26 
28 
-public class MethodDemo 3 { 
public static void main (String[] 
args) { 
/ *int a 
1; 
int b = 2; 
change (a, b) ; 
System. out .println (a) ; 
System. out .println (b) ; 
int[] arr = 
//1 
// 21 
System. out . println (arr [2] ) ; 
change (arr) ; 
System. out . println (arr [2] ) ; 
// 100 
public static void change (int[] 
arr) { 
arr[2] = 
100 
public static void change (int a, int b) { 
a = a+b; 
b = b+a;

 

重写随机点名器

根据不同功能封装成不同的方法

imvu•rt java. util. Scanner; 
Java. . Random; 
public class Call Name { 
public static void main (SC Iing[] args) { 
SC ling [ ] students—new S Cling [S] ; 
addSCudenCName (students) ; 
printSCudenCName (students) ; 
System. ouc . print In (randomSCudenCName (students) ) ; 
public static void addSCudenCName (SC ling [ ] students) { 
Scanner sc=new Scanner (System. in) ; 
for (int i=C' . length; 1++) { 
System. out ( 
students [i] —sc. next ( ) ; 
public static void printSCudenCName (SC ling [ ] 
for (int i=C' . length; i-*) { 
System. ouc . printin (students ; 
I eturn 
students) { 
public static String randomSCudenCName (SC Iing[] 
Random Ian—new Random ( ) ; 
int index=ran.nextlnt (students . length) ; 
return students [index] ; 
students) {

 

 

 

import java.util.Scanner;

public class Shopp{
    public static void main(String[] args){ //定义数组 //品牌 String,尺寸double,价格double,库存 int。  String[] brands={"MacBookAir","ThinkpadT450","ASUS_FL5800"}; double[] sizes={13.3,14,15.6}; double[] prices={6988.88,5999.99,4999.5}; int[] counts={5,10,18}; while(true){ int choose=ChooseFunction(); switch(choose){ case 1: //调用printStore,打印商品信息  PrintStore(brands,sizes,prices,counts); break; case 2: //修改商品信息  UpdateStore(brands,counts); break; case 3: return; default : System.out.println("---------------------------------"); System.out.println("您输入的数据有误,请重新输入:"); break; } } //ChooseFunction(); //调用PrintStore,打印商品信息 //PrintStore(brands,sizes,prices,counts);  } public static void PrintStore(String[] brands,double[] sizes,double[] prices,int[] counts){ //定义累加和 int totalCount=0; double totalPrice=0.0; //输出表头文字 System.out.println("------------------商城库存清单-------------------------------"); System.out.println("品牌型号 尺寸 价格 库存数"); //遍历输出数组元素 for(int i=0;i<brands.length;i++){ System.out.println(brands[i]+" "+sizes[i]+" "+prices[i]+" "+counts[i]); totalCount+=counts[i]; totalPrice+=prices[i]*counts[i]; } //输出总金额 System.out.println("总库存数:"+totalCount); System.out.println("库存商品总金额:"+totalPrice); } public static int ChooseFunction(){ System.out.println("---------------库存管理------------------"); System.out.println("1、查看库存清单"); System.out.println("2、修改商品库存数量"); System.out.println("3、退出"); System.out.println("请输入需要执行的程序编号:"); //接收键盘的输入 Scanner sc=new Scanner(System.in); int choose=sc.nextInt(); return choose; } public static void UpdateStore(String[] brands,int[] counts){ //接收键盘输入 Scanner sc=new Scanner(System.in); //遍历数组 for(int i=0;i<counts.length;i++){ System.out.println("请修改"+brands[i]+"的库存数量:"); //键盘输入,录入库存数组 int newcount=sc.nextInt(); counts[i]=newcount; } } }


猜你喜欢

转载自www.cnblogs.com/ekkor/p/11847882.html