我的java之路week2类的无参、带参方法

2.1语法

public 返回值类型 方法名（）{

//方法体

}

2.2方法的调用语法

对象名.方法名

计算平均分和总成绩

 public class Score {
     /**
      * 创建类 ScoreCalc 编写方法实现各功能 编写测试类
      *  从键盘接收三门课分数，（java c# db）
      *  计算三门课的平均分和总成绩，
      * 编写成绩计算类实现功能 _______
      */
     int java;
     int c;
     int db;

     public double avg() {
         double a = (double) (java + c + db) / 3;
         return a;
     }

     public int addAll() {

         int ad = java + c + db;
         return ad;
     }

 }

Score

 import java.util.Scanner;

 public class TestScore {
     public static void main(String[] args) {
         Score sc=new Score();
         Scanner input=new Scanner(System.in);
         System.out.println("请输入java成绩：");
         sc.java=input.nextInt();
         System.out.println("请输入c成绩：");
         sc.c=input.nextInt();
         System.out.println("请输入db成绩：");
         sc.db=input.nextInt();

         System.out.println(sc.addAll());//总成绩
         System.out.println(sc.avg());//平均成绩
     }

 }

TestScore

package week2;

public class Manager {
	String name;
	String password;
	/**
	 * 打印学员信息
	 */

	public void show() {
		System.out.println("管理员名为："+name+"\n密码为："+password);

	}

}

　　

 package week2;

 public class TestManager {
     public static void main(String[] args) {
         Manager manager=new Manager();
         manager.name="王铎";
         manager.password="123";
         manager.show();
     }

 }

TestManager

2.3用数组作为参数

package week2;
public class JavaScore {
	public double avg(int[] scores) {
		int sum = 0;
		double avg1 = 0.0;
		for (int i = 0; i < scores.length; i++) {
			sum = sum + scores[i];

		}
		avg1 = (double) sum / scores.length;

		return avg1;

	}
	public int max(int[] scores) {
		int max1 = scores[0];
		for (int i = 0; i < scores.length; i++) {
			if (max1 < scores[i]) {// 最大值
				max1 = scores[i];

			}
		}
		return max1;

	}

}

　　

package week2;

import java.util.Scanner;

public class TestScore {
	public static void main(String[] args) {
		JavaScore javascore=new JavaScore();
		int []scores=new int [4];
		Scanner input=new Scanner(System.in);
		System.out.println("请输入5名参赛者的平均成绩：");
		for (int i = 0; i < scores.length; i++) {
			scores[i]=input.nextInt();

		}
		//pingj
		javascore.avg(scores);

	}

}

2.4多个参数的方法

package week2;

public class StudentBz {
	String[] names = new String[30];

	// 添加学生信息
	public void addName(String name) {
		for (int i = 0; i < names.length; i++) {
			if (names[i] == null) {
				names[i] = name;
				break;

			}

		}

	}

	// 展示学生信息
	public void nameShow() {
		for (int i = 0; i < names.length; i++) {
			if (names[i] != null) {
				System.out.print(names[i] + ",");

			}

		}

	}

	public boolean searchFind(int start, int end, String name) {
		boolean find = false;// 标识查找的位置
		for (int i = start - 1; i < end; i++) {// i=start-1sss数组下标
			if (names[i].equals(name)) {
				find = true;
				break;

			}

		}

		return find;
	}

	public boolean updateName(String newName, String oldName) {
		boolean find = false;
		// 查找老name
		for (int i = 0; i < names.length; i++) {
			if (oldName.equals(names[i])) {
				names[i] = newName;
				find = true;
				break;

			}

		}
		return find;

	}

}

　　

package week2;

import java.util.Scanner;

public class TestAdd {
	public static void main(String[] args) {
		StudentBz stu=new StudentBz();
		for (int i = 0; i < 3; i++) {
			Scanner input=new Scanner(System.in);
			System.out.print("请输入学生姓名：");
			String na=input.next();
			stu.addName(na);

		}

		stu.nameShow();

		boolean result=stu.searchFind(2, 5, "name2");
		System.out.println(result);

		boolean updateResult=stu.updateName("newName", "name2");
		System.out.println("是否修改成功"+updateResult);
		stu.nameShow();
	}

}

　　2.5对象作为参数

 package week2;

 public class Student {
     String name;
     int age;
     int no;
     int score;

 }

Student

 package week2;

 public class StudentBz2 {

     Student students[] = new Student[30];

     public void addStudent(Student student) {
         for (int i = 0; i < students.length; i++) {
             if (students[i] == null) {
                 students[i] = student;
                 break;
             }

         }

     }

     public void showStudent() {
         for (int i = 0; i < students.length; i++) {
             if (students[i] != null) {
                 System.out.println(students[i].name + "," + students[i].age
                         + "," + students[i].no + "," + students[i].score + ",");

             }

         }

     }

 }

StudentBz2

 package week2;

 import java.util.Scanner;

 public class TestStudentBz2 {
     public static void main(String[] args) {
         StudentBz2 stubz=new StudentBz2();
         Scanner input=new Scanner(System.in);
         for (int i = 0; i < 2; i++) {
             Student stu=new Student();//循环几次出现几个对象
             System.out.print("请输入姓名：");
             stu.name=input.next();
             System.out.print("请输入年龄：");
             stu.age=input.nextInt();
             System.out.print("请输入学号：");
             stu.no=input.nextInt();
             System.out.print("请输入成绩：");
             stu.score=input.nextInt();
             stubz.addStudent(stu);
         }
         System.out.println();

         stubz.showStudent();

     }

 }

TestStudentBz2

练习实现对客户姓名的排序

 package week2;

 import java.util.Arrays;

 public class KH {

     public void sortName(String []names) {
         Arrays.sort(names);

     }
 }

KH

 package week2;

 public class KHTest {
     public static void main(String[] args) {
         String []names={"j","sds","sdssf","ssf"};
         KH kh=new KH();
         System.out.println("排序前");
         for (int i = 0; i < names.length; i++) {
             if (names[i]!=null) {
                 System.out.println(names[i]+",");

             }

         }
         kh.sortName(names);
         System.out.println("排序后");
         for (int i = 0; i < names.length; i++) {
             if (names[i]!=null) {
                 System.out.println(names[i]+",");

             }

         }
     }

 }

KHTest

带参数练习

 package week2;

 public class CustomerBiz {
     String []customer=new String[30];

     public void addName(String name) {
         for (int i = 0; i < customer.length; i++) {
             if (customer[i]==null) {
                 customer[i]=name;
                 break;

             }

         }

     }

     public void showNames() {
         System.out.println("*****************");
         System.out.println("客户姓名列表");

         for (int i = 0; i < customer.length; i++) {
             if (customer[i]!=null) {
                 System.out.println(customer[i]+",");

             }

         }

     }

 }

CustomerBiz

 package week2;

 import java.util.Scanner;

 public class TestCustomer {
     public static void main(String[] args) {
         boolean con = false;
         CustomerBiz cust = new CustomerBiz();
         Scanner input = new Scanner(System.in);

         for (int i = 0; i < 3; i++) {
             System.out.print("请输入客户姓名：");
             String na = input.next();
             cust.addName(na);
             System.out.println("是否继续（y/n）");
             String n = input.next();

             if (!n.equals("y")) {

             }

         }
         cust.showNames();

     }

 }

TestCustomer