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
1 public class Score { 2 /** 3 * 创建类 ScoreCalc 编写方法实现各功能 编写测试类 4 * 从键盘接收三门课分数，（java c# db） 5 * 计算三门课的平均分和总成绩， 6 * 编写成绩计算类实现功能 _______ 7 */ 8 int java; 9 int c; 10 int db; 11 12 public double avg() { 13 double a = (double) (java + c + db) / 3; 14 return a; 15 } 16 17 public int addAll() { 18 19 int ad = java + c + db; 20 return ad; 21 } 22 23 }
1 import java.util.Scanner; 2 3 4 public class TestScore { 5 public static void main(String[] args) { 6 Score sc=new Score(); 7 Scanner input=new Scanner(System.in); 8 System.out.println("请输入java成绩："); 9 sc.java=input.nextInt(); 10 System.out.println("请输入c成绩："); 11 sc.c=input.nextInt(); 12 System.out.println("请输入db成绩："); 13 sc.db=input.nextInt(); 14 15 System.out.println(sc.addAll());//总成绩 16 System.out.println(sc.avg());//平均成绩 17 } 18 19 }
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);
}
}
1 package week2; 2 3 public class TestManager { 4 public static void main(String[] args) { 5 Manager manager=new Manager(); 6 manager.name="王铎"; 7 manager.password="123"; 8 manager.show(); 9 } 10 11 }
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
1 package week2; 2 3 public class Student { 4 String name; 5 int age; 6 int no; 7 int score; 8 9 }
1 package week2; 2 3 public class StudentBz2 { 4 5 Student students[] = new Student[30]; 6 7 public void addStudent(Student student) { 8 for (int i = 0; i < students.length; i++) { 9 if (students[i] == null) { 10 students[i] = student; 11 break; 12 } 13 14 } 15 16 } 17 18 public void showStudent() { 19 for (int i = 0; i < students.length; i++) { 20 if (students[i] != null) { 21 System.out.println(students[i].name + "," + students[i].age 22 + "," + students[i].no + "," + students[i].score + ","); 23 24 } 25 26 } 27 28 } 29 30 }
1 package week2; 2 3 import java.util.Scanner; 4 5 public class TestStudentBz2 { 6 public static void main(String[] args) { 7 StudentBz2 stubz=new StudentBz2(); 8 Scanner input=new Scanner(System.in); 9 for (int i = 0; i < 2; i++) { 10 Student stu=new Student();//循环几次出现几个对象 11 System.out.print("请输入姓名："); 12 stu.name=input.next(); 13 System.out.print("请输入年龄："); 14 stu.age=input.nextInt(); 15 System.out.print("请输入学号："); 16 stu.no=input.nextInt(); 17 System.out.print("请输入成绩："); 18 stu.score=input.nextInt(); 19 stubz.addStudent(stu); 20 } 21 System.out.println(); 22 23 stubz.showStudent(); 24 25 } 26 27 }
练习实现对客户姓名的排序
1 package week2; 2 3 import java.util.Arrays; 4 5 public class KH { 6 7 public void sortName(String []names) { 8 Arrays.sort(names); 9 10 } 11 }
1 package week2; 2 3 public class KHTest { 4 public static void main(String[] args) { 5 String []names={"j","sds","sdssf","ssf"}; 6 KH kh=new KH(); 7 System.out.println("排序前"); 8 for (int i = 0; i < names.length; i++) { 9 if (names[i]!=null) { 10 System.out.println(names[i]+","); 11 12 } 13 14 } 15 kh.sortName(names); 16 System.out.println("排序后"); 17 for (int i = 0; i < names.length; i++) { 18 if (names[i]!=null) { 19 System.out.println(names[i]+","); 20 21 22 } 23 24 25 } 26 } 27 28 }
带参数练习
1 package week2; 2 3 public class CustomerBiz { 4 String []customer=new String[30]; 5 6 public void addName(String name) { 7 for (int i = 0; i < customer.length; i++) { 8 if (customer[i]==null) { 9 customer[i]=name; 10 break; 11 12 } 13 14 15 } 16 17 18 } 19 20 21 public void showNames() { 22 System.out.println("*****************"); 23 System.out.println("客户姓名列表"); 24 25 for (int i = 0; i < customer.length; i++) { 26 if (customer[i]!=null) { 27 System.out.println(customer[i]+","); 28 29 } 30 31 32 } 33 34 35 36 } 37 38 }
1 package week2; 2 3 import java.util.Scanner; 4 5 public class TestCustomer { 6 public static void main(String[] args) { 7 boolean con = false; 8 CustomerBiz cust = new CustomerBiz(); 9 Scanner input = new Scanner(System.in); 10 11 for (int i = 0; i < 3; i++) { 12 System.out.print("请输入客户姓名："); 13 String na = input.next(); 14 cust.addName(na); 15 System.out.println("是否继续（y/n）"); 16 String n = input.next(); 17 18 if (!n.equals("y")) { 19 20 } 21 22 } 23 cust.showNames(); 24 25 } 26 27 }