第一个小项目
package venus;
import java.util.Scanner;
public class Main {
static int index = 0;
static Student [] students = new Student[45];
public static void main(String[] args) {
System.out.println("-----------------------");
System.out.println("- 欢迎使用学生管理系统 -");
System.out.println("-----------------------");
for(;;) {
menu();
}
}
private static void menu() {
System.out.println("1、添加学生信息");
System.out.println("2、删除学生信息");
System.out.println("3、修改学生信息");
System.out.println("4、查询学生信息");
System.out.println("请输入操作项,点击Enter键");
Scanner scanner = new Scanner(System.in);
int option = scanner.nextInt();
switch(option) {
case 1:{
System.out.println("添加学生信息");
if(index>students.length-1) {
System.out.println("已经没有座位了");
break;
}
Student student = new Student();
System.out.println("请输入学号,点击Enter键");
String id = scanner.next();
student.setId(id);
if(index!=0) {
for(Student stu : students) {
if(stu==null) {
break;
}
if(stu.getId().equals(student.getId())) {
System.out.println("此学号已存在,请确认是否输入正确");
return;
}
}
}
System.out.println("请输入姓名,点击Enter键");
String name = scanner.next();
student.setName(name);
System.out.println("请输入手机号,点击Enter键");
String mobile = scanner.next();
student.setMobile(mobile);
System.out.println("请输入地址,点击Enter键");
String address = scanner.next();
student.setAddress(address);
students[index]=student;
index = index +1;
System.out.println(index);
System.out.println("添加成功");
break;
}
case 2:{
System.out.println("删除学生信息");
System.out.println("请输入学号,点击Enter键");
String id = scanner.next();
boolean hasData=false;
int i= 0;
for(;i<students.length;i++) {
if(students[i]==null) {
break;
}
if(id.equals(students[i].getId())) {
hasData=true;
break;
}
}
if(!hasData) {
System.out.println("没有找到学号为"+id+"的学生信息");
return;
}
for (; i < students.length; i++) {
if(i==students.length-1) {
students[i]=null;
break;
}
students[i] = students[i+1];
if (students[i+1]==null) {
break;
}
}
System.out.println("删除成功");
index=index-1;
return;
//牛逼代码
/*for(int i=1;i<=index;i++) {
if(students[i].getId().equals(id)) {
students[i]=studnets[index-1];
students[index-1]=null;
index--;
System.out.println("删除成功");
return;
}
}
System.out.println("无此学生信息");
break;*/
/*int i,j;
for(i=0;i<=45;i++) {
if(students[i].getId().equals(id)) {
break;
}
}
if(i<45) {
if(i<=43) {
for(j=i;j<44;j++) {
students[j]=students[j+1];
}
}
}else {
System.out.println("输入学号不存在,请核实信息");
}
System.out.println("删除成功");
break;*/
}
case 3:{
System.out.println("修改学生信息");
boolean hasData = false;
System.out.println("请输入学号,点击Enter键");
String id = scanner.next();
for(Student student:students) {
if(student==null) {
break;
}
if(student.getId().equals(id)) {
System.out.println("请输入姓名,点击Enter键");
String name = scanner.next();
student.setName(name);
System.out.println("请输入手机号,点击Enter键");
String mobile = scanner.next();
student.setMobile(mobile);
System.out.println("请输入地址,点击Enter键");
String address = scanner.next();
student.setAddress(address);
System.out.println("修改成功");
hasData=true;
return;
}
}
if(!hasData) {
System.out.println("没有找到学号为"+id+"的学生信息");
}
break;
}
case 4:
System.out.println("查询学生信息");
boolean hasData=false;
System.out.println("请输入姓名,点击Enter键");
String name = scanner.next();
for(Student student:students) {
if(student==null) {
break;
}
if(student.getName().equals(name)) {
System.out.println(student);
hasData=true;
}
}
if(!hasData) {
System.out.println("没有找到姓名为"+name+"的学生信息");
}
//return;
break;
default:
System.out.println("系统没有找到"+option+"操作项!");
}
}
}