用java写一个简单学生成绩管理系统

以下是一个简单的学生成绩管理系统的Java代码：

import java.util.Scanner;

public class StudentGradeManagementSystem {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int numStudents = 0;
int[] studentIds = new int[100];
String[] studentNames = new String[100];
double[] studentGrades = new double[100];
int choice;

do {
System.out.println("== 学生成绩管理系统 ==");
System.out.println("1. 添加学生");
System.out.println("2. 修改学生");
System.out.println("3. 删除学生");
System.out.println("4. 查询学生信息");
System.out.println("5. 显示所有学生信息");
System.out.println("0. 退出系统");
System.out.print("请选择操作：");
choice = scanner.nextInt();

switch (choice) {
case 1:
System.out.print("请输入学生学号：");
int id = scanner.nextInt();
System.out.print("请输入学生姓名：");
String name = scanner.next();
System.out.print("请输入学生成绩：");
double grade = scanner.nextDouble();
studentIds[numStudents] = id;
studentNames[numStudents] = name;
studentGrades[numStudents] = grade;
numStudents++;
System.out.println("添加学生成功！");
break;
case 2:
System.out.print("请输入要修改的学生学号：");
int modifyId = scanner.nextInt();
int modifyIndex = -1;
for (int i = 0; i < numStudents; i++) {
if (studentIds[i] == modifyId) {
modifyIndex = i;
break;
}
}
if (modifyIndex != -1) {
System.out.print("请输入新的学生姓名：");
String modifyName = scanner.next();
System.out.print("请输入新的学生成绩：");
double modifyGrade = scanner.nextDouble();
studentNames[modifyIndex] = modifyName;
studentGrades[modifyIndex] = modifyGrade;
System.out.println("修改学生信息成功！");
} else {
System.out.println("学号为 " + modifyId + " 的学生不存在！");
}
break;
case 3:
System.out.print("请输入要删除的学生学号：");
int deleteId = scanner.nextInt();
int deleteIndex = -1;
for (int i = 0; i < numStudents; i++) {
if (studentIds[i] == deleteId) {
deleteIndex = i;
break;
}
}
if (deleteIndex != -1) {
for (int i = deleteIndex; i < numStudents - 1; i++) {
studentIds[i] = studentIds[i + 1];
studentNames[i] = studentNames[i + 1];
studentGrades[i] = studentGrades[i + 1];
}
numStudents--;
System.out.println("删除学生成功！");
} else {
System.out.println("学号为 " + deleteId + " 的学生不存在！");
}
break;
case 4:
System.out.print("请输入要查询的学生学号：");
int searchId = scanner.nextInt();
int searchIndex = -1;
for (int i = 0; i < numStudents; i++) {
if (studentIds[i] == searchId) {
searchIndex = i;
break;
}
}
if (searchIndex != -1) {
System.out.println("学号：" + studentIds[searchIndex]);
System.out.println("姓名：" + studentNames[searchIndex]);
System.out.println("成绩：" + studentGrades[searchIndex]);
} else {
System.out.println("学号为 " + searchId + " 的学生不存在！");
}
break;
case 5:
System.out.println("== 所有学生信息 ==");
System.out.println("学号\t姓名\t成绩");
for (int i = 0; i < numStudents; i++) {
System.out.println(studentIds[i] + "\t" + studentNames[i] + "\t" + studentGrades[i]);
}
break;
case 0:
System.out.println("感谢使用学生成绩管理系统！");
break;
default:
System.out.println("输入的操作不正确，请重新输入！");
break;
}
} while (choice != 0);
}
}