Grade類:用來存儲學生的信息
import java.io.Serializable;
class Grade implements Serializable{
private int id;
private String name;
private double math;
private double english;
private double java;
private double computer;
private double average;
public Grade(int id ,String name, double math, double english,double java,double computer) {
this.id=id;
this.name=name;
this.math=math;
this.english=english;
this.java=java;
this.computer=computer;
average=(math+english+java+computer)/4;
}
@Override
public String toString() {
return "Grade [id=" + id + ", name=" + name + ", math=" + math + ", english=" + english + ", java=" + java
+ ", computer=" + computer + "]";
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getMath() {
return math;
}
public void setMath(double math) {
this.math = math;
}
public double getEnglish() {
return english;
}
public void setEnglish(double english) {
this.english = english;
}
public double getJava() {
return java;
}
public void setJava(double java) {
this.java = java;
}
public double getComputer() {
return computer;
}
public void setComputer(double computer) {
this.computer = computer;
}
public double getaverage() {
return average;
}
}
GradeLis類提供一些方法。例:添加成績信息,刪除成績,查看平均成績等方法
import java.util.Arrays;
public class GradeList {
static Grade[] grade;
public static int studentCount;
private int subject;
/*
*Grade默認構造函數
*/
public GradeList() {
this(10);
}
public GradeList(int size) {
this.grade=new Grade[size];
this.studentCount=0;
this.subject=4;
}
/*
*顯示成績信息函數
*/
public void show() {
if(studentCount == 0) {
System.out.println("nothing!");
}
averagesort(); //調用平均成績排序函數
for(int i=0;i<studentCount;i++) {
System.out.println(grade[i]);
}
}
/*
* 平均成績排序
*/
private void averagesort() {
// TODO Auto-generated method stub
for(int i=0;i<studentCount-1;i++) {
for(int j=0;j<studentCount-1-i;j++) {
if(grade[j].getaverage()<grade[j+1].getaverage()) {
Grade temp=grade[j];
grade[j]=grade[j+1];
grade[j+1]=temp;
}
}
}
}
/*
* 查找最高分
*/
public void searchMax(int option) {
double Mmax= grade[0].getMath(),Emax=grade[0].getEnglish(),Jmax=grade[0].getJava(),Cmax=grade[0].getComputer();
switch(option) {
case 1: // 數學最高分
for(int i=0;i<studentCount;i++) {
if(grade[i].getMath() > Mmax) {
Mmax = grade[i].getMath();
}
}
System.out.println("數學最高分 :"+Mmax);
break;
case 2: //英語最高分
for(int i=0;i<studentCount;i++) {
if(grade[i].getEnglish() > Emax) {
Emax =grade[i].getEnglish();
}
}
System.out.println("英語最高分: "+Emax);
break;
case 3: //java最高分
for(int i=0;i<studentCount;i++) {
if(grade[i].getJava()> Jmax) {
Jmax = grade[i].getJava();
}
}
System.out.println("java最高分 : "+Jmax);
break;
case 4: //計算機基礎最高分
for(int i=0;i<studentCount;i++) {
if(grade[i].getComputer() > Cmax) {
Cmax =grade[i].getComputer();
}
}
System.out.println("計算機基礎最高分: "+Cmax);
break;
}
}
/*
* 查最低分
*/
public void searchMin(int option) {
double Mmin=grade[0].getMath(),Emin=grade[0].getEnglish(),Jmin=grade[0].getJava(),Cmin=grade[0].getComputer();
switch(option) {
//數學最低分
case 1:
for(int i=0;i<studentCount;i++) {
if(grade[i].getMath() < Mmin) {
Mmin = grade[i].getMath();
}
}
System.out.println("數學最低分: "+Mmin);
break;
case 2: //英語最低分
for(int i=0;i<studentCount;i++) {
if(grade[i].getEnglish() < Emin) {
Emin =grade[i].getEnglish();
}
}
System.out.println("英語最低分: "+Emin);
break;
case 3: //java最低分
for(int i=0;i<studentCount;i++) {
if(grade[i].getJava() < Jmin) {
Jmin = grade[i].getJava();
}
}
System.out.println("java最低分: "+Jmin);
break;
case 4: //計算機基礎最低分
for(int i=0;i<studentCount;i++) {
if(grade[i].getComputer() < Cmin) {
Cmin =grade[i].getComputer();
}
}
System.out.println("計算機基礎最低分: "+Cmin);
break;
}
}
/*
* 輸出平均成績函數
*/
public void average() {
double M_ave=0,E_ave=0,J_ave=0,C_ave=0; // 分別代表數學,英語,Java,計算機基礎 平均成績
double MathSum=0,EnglishSum=0,JavaSum=0,ComputerSum=0;
//數學平均成績計算
for(int i=0;i<studentCount;i++) {
MathSum+=grade[i].getMath();
}
M_ave=MathSum/this.subject;
// 英語平均成績計算
for(int i=0;i<studentCount;i++) {
EnglishSum+=grade[i].getEnglish();
}
E_ave=EnglishSum/this.subject;
//Java平均成績計算
for(int i=0;i<studentCount;i++) {
JavaSum+=grade[i].getJava();
}
J_ave=JavaSum/this.subject;
// 計算機基礎平均成績計算
for(int i=0;i<studentCount;i++) {
ComputerSum+=grade[i].getComputer();
}
C_ave=ComputerSum/this.subject;
System.out.println("數學平均成績: "+M_ave);
System.out.println("英語平均成績: "+E_ave);
System.out.println("Java平均成績: "+J_ave);
System.out.println("計算機基礎平均成績: "+C_ave);
}
/*
* 添加信息函數
*/
public void add(Grade gradetest) {
/*
* 如果學生人數等於數組長度,進行擴容
*/
if (studentCount == grade.length) {
grade = Arrays.copyOf(grade, 2 * studentCount);
}
grade[studentCount] = gradetest;
studentCount++;
}
/*
* 查找信息函數
*/
public void search(String name) {
// TODO Auto-generated method stub
int i=0;
for(;i<studentCount;i++) {
if(grade[i].getName().equals(name)) {
System.out.println(grade[i]);
break;
}
}
}
}
主函數:
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Arrays;
import java.util.Scanner;
public class GradeManage {
public static Scanner in=new Scanner(System.in);
public static GradeList gradelist=new GradeList();
public static void main(String[] args) {
// TODO Auto-generated method stubarg0
File file=new File("student.txt");
try {
if(file.exists()) {
FileInputStream fInputStream = new FileInputStream(file);
ObjectInputStream objectInputStream =new ObjectInputStream(fInputStream);
GradeList.grade=(Grade[])objectInputStream.readObject();
GradeList.studentCount = objectInputStream.readInt();
objectInputStream.close();
}
}catch(Exception e1){
}
while(true) {
System.out.println("----------------------------------");
System.out.println(" 1.顯示成績信息(按平均成績降序) ");
System.out.println(" 2.查詢各科最高分,最低分");
System.out.println(" 3.查詢平均成績");
System.out.println(" 4.添加學生成績信息");
System.out.println(" 5.查詢學生成績");
System.out.println(" 6.退出系統");
System.out.println("----------------------------------");
int option=in.nextInt();
if(option==6) {
try {
FileOutputStream fOutputStream = new FileOutputStream("student.txt");
ObjectOutputStream objectOutputStream =new ObjectOutputStream(fOutputStream);
objectOutputStream.writeObject(GradeList.grade);
objectOutputStream.writeInt(GradeList.studentCount);
objectOutputStream.close();
}catch(Exception e1){
}
break;
}
switch(option) {
case 1:
gradelist.show(); //顯示所有成績信息(按平均成績降序)
break;
case 2:
System.out.println(" 請輸入你想查詢的科目成績(最高分,最低分): 1/數學,2/英語,/3java,4/計算機基礎");
int choice=in.nextInt();
gradelist.searchMax(choice); //查詢各科最高分
gradelist.searchMin(choice); //查詢各科最低分
break;
case 3:
gradelist.average(); //平均成績
break;
case 4:
add(); //添加信息
break;
case 5:
System.out.println(" 請輸入 id: ");
gradelist.search(in.nextLine()); //查詢學生成績
}
}
System.out.println(" 謝謝使用 !");
}
/*
* 添加學生信息
*/
private static void add() {
// TODO Auto-generated method stub
System.out.println("請輸入信息,請以逗號分割:(學號,姓名,數學成績,英語成績,java成績,計算機成績)");
in.nextLine(); //讀取回車鍵
String input = in.nextLine();
String[] str = input.split(",");
for(int i=0; i<str.length; ++i){
str[i] = str[i].trim(); // trim把字符串前後多餘的空格去調
}
Grade gradetest = new Grade(Integer.parseInt(str[0]),
str[1], Double.parseDouble(str[2]),Double.parseDouble(str[3]),
Double.parseDouble(str[4]),Double.parseDouble(str[5]));
gradelist.add(gradetest); //調用添加函數
}