第一个小项目

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！");
	    
	    }
		

	}
}