9.6笔记

import javax.swing.JOptionPane;




public class Class96 {
public static int[] codeArray=new int[20];
public static String[] nameArray=new String[20];
public static int[] gradeArray=new int[20];
public static int num=0;
public static void main(String[] args) {


JOptionPane.showMessageDialog(null,"欢迎使用！");
boolean isLogin=login();
if(isLogin==false){
JOptionPane.showMessageDialog(null,"非法输入！");
System.exit(0);
}

while(true){
String str=JOptionPane.showInputDialog(null,"1: 添加\n2: 显示\n3: 删除\n4: 修改\n5: 查询\n6: 排序\n7: 退出");
int item=Integer.parseInt(str);
switch(item){
case 1:add();break;
case 2:show();break;
case 3:del();break;
case 4:change();break;
case 5:cx();break;
case 6:px();break;
case 7:System.exit(0);
default:JOptionPane.showMessageDialog(null,"请输入有效选项");

}
}

} 
//登录
public static boolean login(){
for(int i=0;i<3;i++){
String myuser=JOptionPane.showInputDialog(null,"请输入用户名");
String mypwd=JOptionPane.showInputDialog(null,"请输入密码");


if("666666".equals(myuser)  &&  "123456".equals(mypwd)){
JOptionPane.showMessageDialog(null,"登陆成功");
return true;
}else{
JOptionPane.showMessageDialog(null,"用户名或密码错误");
}
}return false;

}

//添加①
public static void add(){
String codeStr=JOptionPane.showInputDialog(null,"请输入学号");
String nameStr=JOptionPane.showInputDialog(null,"姓名");
String gradeStr=JOptionPane.showInputDialog(null,"成绩");

codeArray[num]=Integer.parseInt(codeStr);
nameArray[num]=nameStr;
gradeArray[num]=Integer.parseInt(gradeStr);

num++;

}
//显示②
public static void show(){
String info="学号/ 姓名/成绩\n";
for(int i=0;i<num;i++){
info +=codeArray[i]+"/"+nameArray[i]+"/"+gradeArray[i]+"\n";

}JOptionPane.showMessageDialog(null,info);
}
//排序⑥
public static void px(){

for(int i=0;i<gradeArray.length;i++){
for(int j=i+1;j<gradeArray.length;j++){
if(gradeArray[i]<gradeArray[j]){
int temp=gradeArray[i];
gradeArray[i]=gradeArray[j];
gradeArray[j]=temp;

String x=nameArray[i];
nameArray[i]=nameArray[j];
nameArray[j]=x;
}
}
}
String str="";
for(int i=0;i<nameArray.length;i++){
str +=nameArray[i]+"   "+gradeArray[i]+"\n";
}
JOptionPane.showMessageDialog(null,str);

}
//查询⑤
public static void cx(){
int index=-1;
String name=JOptionPane.showInputDialog(null,"请输入人名");
for(int i=0;i<num;i++){
if(name.equals(nameArray[i])){
index=i;
break;
}
}if(index==-1){
JOptionPane.showMessageDialog(null,"查无此人");
}else{
JOptionPane.showMessageDialog(null,name+"的成绩为"+gradeArray[index]);}
}
//修改 ④
public static void change(){
int index=findName();
if(index !=-1){
String codeStr=JOptionPane.showInputDialog(null,"请输入新的学号");
String nameStr=JOptionPane.showInputDialog(null,"请输入新的姓名");
String gradeStr=JOptionPane.showInputDialog(null,"请输入新的成绩");

codeArray[index]=Integer.parseInt(codeStr);
nameArray[index]=nameStr;
gradeArray[index]=Integer.parseInt(gradeStr);}
show();
}

//查找姓名
public static int findName(){
String name=JOptionPane.showInputDialog(null,"请输入姓名");
for(int i=0;i<num;i++){
if(name.equals(nameArray[i])){
return i;
}
}
JOptionPane.showInputDialog(null,"请输入正确的学生姓名");
return -1;
}
//删除③
public static void del(){
int index= findName();
if(index != -1){;

for(int i=index;i<num;i++){
codeArray[i]=codeArray[i+1];
nameArray[i]=nameArray[i+1];
gradeArray[i]=gradeArray[i+1];
}
}num--;
show();
}
}