简单的员工管理系统

package com.niubi;
import java.util.*;
import java.io.*;
public class demo7 {

	public static void main(String[] args) throws Exception{
		// TODO Auto-generated method stub
      manage em=new manage();
      BufferedReader br=new BufferedReader(new InputStreamReader (System.in));
      while(true) {
    	  System.out.println("请选择你要进行的操作");
    	  System.out.println("1:添加一个雇员");
    	  System.out.println("2:查找一个雇员");
    	  System.out.println("3:修改一个雇员的工资");
    	  System.out.println("4:删除一个雇员");
    	  System.out.println("5:退出系统");
    	  String iii=br.readLine();
    	  if(iii.endsWith("1")) 
    	  {
    		  System.out.println("请输入新员工编号");
    		  String num=br.readLine();
    		  System.out.println("请输入新员工姓名");
    		  String name=br.readLine();
    		  System.out.println("请输入新员工薪水");
    		  float sal=Float.parseFloat(br.readLine());
    		  Emp emp=new Emp(num,name,sal);
    		  em.add(emp);
    	  }
    	  else if(iii.endsWith("2")) 
    	  {
    		  System.out.println("请输入员工编号");
    		  String num=br.readLine();
    		  em.show(num);
    	  }
    	  else if(iii.endsWith("3")) 
    	  {
    		  System.out.println("请输入员工编号");
    		  String num=br.readLine();
    		  System.out.println("请输入员工薪水");
    		  float newsal=Float.parseFloat(br.readLine());
    		  em.updatsal(num, newsal);
    	  }
    	  else if(iii.endsWith("4")) 
    	  {
    		  System.out.println("请输入员工编号");
    		  String num=br.readLine();
    		  em.del(num);
    	  }
    	  else if(iii.endsWith("5")) 
    	  {
    		  System.exit(0);
    	  }
      }
	}

}
class Emp{
	private String num;
	private String name;
	private float sal;
	public Emp(String num,String name,float sal) {
		this.num=num;
		this.name=name;
		this.sal=sal;
		 
	}
	public String getNum() {
		return num;
	}
	public void setNum(String num) {
		this.num = num;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public float getSal() {
		return sal;
	}
	public void setSal(float sal) {
		this.sal = sal;
	}
	
	
}
class manage
{
	private ArrayList al=null;
	public manage()
	{
		al=new ArrayList();
	}
	public void add(Emp emp) {
		al.add(emp);
	}
	public void show(String num) {
		for(int i=0;i