Java学生成绩查询系统系统

灰太狼 2024-03-24 08:39 44阅读 0赞

项目要求：

①学生成绩查询系统中保存学生姓名、课程名称以及学生的课程成绩。

②查询系统从控制台输入统计命令以及参数，实现成绩的查询。主要命令如下：

avg Java：统计课程Java的平均分。

avg song：统计学生song的平均分。

get song Java：获取学生song的Java课程的成绩。

sort Java：列出Java 课程的成绩排序结果。

exit：退出程序。

数据储存：

如果查询的学生或课程不存在时，给出相应的提示。

学生的名字和课程的名称分别存在一维数组中：

static String\[ \] students=\{"zhang","wang"，"li","zhao"，"liu"、"song"\};

static String\[ \]courses =\{"C","Java","mySQL"，"Linux"，"HTML"\};

学生成绩存在二维数组中：

static int\[ \]\[ \] score =new int\[6\]\[5\];

初始化数组，输出数组即显示成绩，执行查询系统的控制台命令调度。

import java.util.*;
    public class StudentScore
    {	 
    	 static final int STUDENT_NUM=6;
    	 static final int COURSE_NUM=5;
    	 static String[] students={"zhang","wang","li","zhao","liu","song"};
    	 static String[] courses={"C","Java","mySQL","Linux","HTML"};
    		
    	 
    
    	 public static void main(String[] args){
    		  double[][] score={
       {26,69,46,25,5},{27,10,24,66,58},{44,58,0,82,75},{6,68,92,9,84},{75,1,51,41,74},{23,38,65,1,55}}; //定义二维数组记录学生成绩;
    	      double ave_c,ave_java,ave_mysql,ave_linux,ave_html;	//定义课程平均成绩
    	 ave_c=(score[0][0]+score[1][0]+score[2][0]+score[3][0]+score[4][0]+score[5][0])/6;
    	 ave_java=(score[0][1]+score[1][1]+score[2][1]+score[3][1]+score[4][1]+score[5][1])/6;
    	 ave_mysql=(score[0][2]+score[1][2]+score[2][2]+score[3][2]+score[4][2]+score[5][2])/6;
    	 ave_linux=(score[0][3]+score[1][3]+score[2][3]+score[3][3]+score[4][3]+score[5][3])/6;
    	 ave_html=(score[0][4]+score[1][4]+score[2][4]+score[3][4]+score[4][4]+score[5][4])/6;
    	  double ave_zhang,ave_wang,ave_li,ave_zhao,ave_liu,ave_song;	//定义学生平均成绩
    	 ave_zhang=(score[0][0]+score[0][1]+score[0][2]+score[0][3]+score[0][4])/5;
    	 ave_wang=(score[1][0]+score[1][1]+score[1][2]+score[1][3]+score[1][4])/5;
    	 ave_li=(score[2][0]+score[2][1]+score[2][2]+score[2][3]+score[2][4])/5;
    	 ave_zhao=(score[3][0]+score[3][1]+score[3][2]+score[3][3]+score[3][4])/5;
    	 ave_liu=(score[4][0]+score[4][1]+score[4][2]+score[4][3]+score[4][4])/5;
    	 ave_song=(score[5][0]+score[5][1]+score[5][2]+score[5][3]+score[5][4])/5;
    	 System.out.println("        C      Java   mySQL  Linux   HTML");
    	 System.out.println("zhang   26     69     46     25      5");
    	 System.out.println("wang    27     10     24     66      58");
    	 System.out.println("li      44     58     0      82      75");
    	 System.out.println("zhao    6      68     92     9       84");
         System.out.println("liu     75     1      51     41      74");
         System.out.println("song    23     38     65     1       55");
    	     Scanner scanner=new Scanner(System.in);
    	     boolean a = true;
    		 while(a){
    		      System.out.printf("请输入命令：");
    			  String command=scanner.nextLine();//输入指令
    			  if(command.startsWith("avg")){  //按照指令输出课程平均分
    				  if(command.equalsIgnoreCase("avg c")){
    			  	   System.out.format("C的平均分是：",ave_c);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg java")){
    			       System.out.format("Java的平均分是：%.2f",ave_java);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg mysql")){
    			       System.out.format("mySQL的平均分是：%.2f",ave_mysql);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg linux")){
    			       System.out.format("Linux的平均分是：%.2f",ave_linux);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg html")){
    			       System.out.format("HTML的平均分是：%.2f",ave_html);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg zhang")){
    			       System.out.format("zhang的平均分是：%.2f",ave_zhang);//输出学生平均分
    				   System.out.println();
    		  	      }else if(command.equalsIgnoreCase("avg wang")){
    			       System.out.format("wang的平均分是：%.2f",ave_wang);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg li")){
    			       System.out.format("li的平均分是：%.2f",ave_li);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg zhao")){
    			       System.out.format("zhao的平均分是：%.2f",ave_zhao);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg liu")){
    			       System.out.format("liu的平均分是：%.2f",ave_liu);
    				   System.out.println();
    			      }else if(command.equalsIgnoreCase("avg song")){
    			       System.out.format("song的平均分是：%.2f",ave_song);
    				   System.out.println();
    			      }else
    			       System.out.println("你输入的既不是课程名，也不是学生名");
    			  }
    			  else if(command.startsWith("get")){
    				   String[] words=command.split(" ");//将字符串按空格分割开
    				   String student=words[1];	//分割开的第二个字符串为学生名·
    				   String course=words[2];	//课程名
    				  if(student.equalsIgnoreCase("zhang")){ //将学生zhang的成绩分类
    					  if(course.equalsIgnoreCase("c")){
    					    System.out.format("zhang的c成绩是：%.2f",score[0][0]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("java")){
    					    System.out.format("zhang的java成绩是：%.2f",score[0][1]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("mysql")){
    					    System.out.format("zhang的mysql成绩是：%.2f",score[0][2]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("linux")){
    					    System.out.format("zhang的linux成绩是：%.2f",score[0][3]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("hyml")){
    					    System.out.format("zhang的html成绩是：%.2f",score[0][4]);
    						System.out.println();
    					  }else{
    					   System.out.println("zhang没有"+course+"这门课程");
    				      }
    				  }
    				   else if(student.equalsIgnoreCase("wang")){//将学生wang成绩分类
    					  if(course.equalsIgnoreCase("c")){
    					    System.out.format("wang的c成绩是：%.2f",score[1][0]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("java")){
    					    System.out.format("wang的java成绩是：%.2f",score[1][1]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("mysql")){
    					    System.out.format("wang的mysql成绩是：%.2f",score[1][2]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("linux")){
    					    System.out.format("wang的linux成绩是：%.2f",score[1][3]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("hyml")){
    					    System.out.format("wang的html成绩是：%.2f",score[1][4]);
    						System.out.println();
    					  }else{
    					   System.out.println("wang没有"+course+"这门课程");
    				      }	
    				   }
    				   else if(student.equalsIgnoreCase("li")){	//将学生li成绩分类
    					  if(course.equalsIgnoreCase("c")){
    					    System.out.format("li的c成绩是：%.2f",score[2][0]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("java")){
    					    System.out.format("li的java成绩是：%.2f",score[2][1]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("mysql")){
    					    System.out.format("li的mysql成绩是：%.2f",score[2][2]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("linux")){
    					    System.out.format("li的linux成绩是：%.2f",score[2][3]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("hyml")){
    					    System.out.format("li的html成绩是：%.2f",score[2][4]);
    						System.out.println();
    					  }else{
    					   System.out.println("li没有"+course+"这门课程");
    				      }
    				   }
    				   else if(student.equalsIgnoreCase("zhao")){ //将学生zhao成绩分类
    					  if(course.equalsIgnoreCase("c")){
    					    System.out.format("zhao的c成绩是：%.2f",score[3][0]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("java")){
    					    System.out.format("zhao的java成绩是：%.2f",score[3][1]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("mysql")){
    					    System.out.format("zhao的mysql成绩是：%.2f",score[3][2]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("linux")){
    					    System.out.format("zhao的linux成绩是：%.2f",score[3][3]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("hyml")){
    					    System.out.format("zhao的html成绩是：%.2f",score[3][4]);
    						System.out.println();
    					  }else{
    					   System.out.println("zhao没有"+course+"这门课程");
    				      }
    				   }
    				   else if(student.equalsIgnoreCase("liu")){ //将学生liu成绩分类
    					  if(course.equalsIgnoreCase("c")){
    					    System.out.format("zhao的c成绩是：%.2f",score[4][0]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("java")){
    					    System.out.format("zhao的java成绩是：%.2f",score[4][1]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("mysql")){
    					    System.out.format("zhao的mysql成绩是：%.2f",score[4][2]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("linux")){
    					    System.out.format("zhao的linux成绩是：%.2f",score[4][3]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("hyml")){
    					    System.out.format("zhao的html成绩是：%.2f",score[4][4]);
    						System.out.println();
    					  }else{
    					   System.out.println("zhao没有"+course+"这门课程");
    				      }
    				   }
    				   else if(student.equalsIgnoreCase("song")){ //将学生song成绩分类
    					  if(course.equalsIgnoreCase("c")){
    					    System.out.format("song的c成绩是：%.2f",score[5][0]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("java")){
    					    System.out.format("song的java成绩是：%.2f",score[5][1]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("mysql")){
    					    System.out.format("song的mysql成绩是：%.2f",score[5][2]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("linux")){
    					    System.out.format("song的linux成绩是：%.2f",score[5][3]);
    						System.out.println();
    					  }else if(course.equalsIgnoreCase("hyml")){
    					    System.out.format("song的html成绩是：%.2f",score[5][4]);
    						System.out.println();
    					  }
    					  else{
    					   System.out.println("song没有"+course+"这门课程");
    				      }
    				   }
    				   else{
    					   System.out.println("没有"+student+"这个人");
    				   }
    				 }
    			  else if(command.startsWith("sort")){
    			      double m;
    			      String t;
    			  	   String[] words=command.split(" ");
    				   String course =words[1];
    				   int[] b=new int[5];
    				   int count=0;
    			  	   if(course.equalsIgnoreCase("c")){
    					   System.out.println("名次    姓名    C");
    				 for (int i = 0; i < 6; i++){
                       for (int j = 0; j < 6 - i - 1; j++){
                        if (score[j][0] > score[j + 1][0]) {
                            m = score[j][0];
                            score[j][0] = score[j + 1][0];
                            score[j + 1][0] = m; // 分数交换
                            t = students[j];
                            students[j] = students[j + 1];
                            students[j + 1] = t; // 名字交换；//这是C的类的成绩排序
                        }
    				   }
    				 }
    				   for(int i=0;i<6;i++){
    					  System.out.println((i+1)+"\t"+students[i]+"\t"+score[i][0]);
    					  }
    				   }
    
    				  else if(course.equalsIgnoreCase("java")){
    					   System.out.println("名次    姓名    Java");
    				 for (int i = 0; i < 6; i++){
                       for (int j = 0; j < 6 - i - 1; j++){
                        if (score[j][1] > score[j + 1][1]) {
                            m = score[j][1];
                            score[j][1] = score[j + 1][1];
                            score[j + 1][1] = m; // 分数交换
                            t = students[j];
                            students[j] = students[j + 1];
                            students[j + 1] = t; // 名字交换；//这是C的类的成绩排序
                        }
    				   }
    				 }
    				   for(int i=0;i<6;i++){
    					  System.out.println((i+1)+"\t"+students[i]+"\t"+score[i][1]);
    					  }
    				   }
    
    				 else if(course.equalsIgnoreCase("mysql")){
    					   System.out.format("名次    姓名    mySQL");
    				 for (int i = 0; i < 6; i++){
                       for (int j = 0; j < 6 - i - 1; j++){
                        if (score[j][2] > score[j + 1][2]) {
                            m = score[j][2];
                            score[j][2] = score[j + 1][2];
                            score[j + 1][2] = m; 
                            t = students[j];
                            students[j] = students[j + 1];
                            students[j + 1] = t;
                        }
    				   }
    				 }
    				   for(int i=0;i<6;i++){
    					  System.out.println((i+1)+"\t"+students[i]+"\t"+score[i][2]);
    					  }
    				   }
    
    				 else if(course.equalsIgnoreCase("linux")){
    					   System.out.println("名次    姓名    Linux");
    				 for (int i = 0; i < 6; i++){
                       for (int j = 0; j < 6 - i - 1; j++){
                        if (score[j][3] > score[j + 1][3]) {
                            m = score[j][3];
                            score[j][3] = score[j + 1][3];
                            score[j + 1][3] = m; // 分数交换
                            t = students[j];
                            students[j] = students[j + 1];
                            students[j + 1] = t; // 名字交换；//这是C的类的成绩排序
                        }
    				   }
    				 }
    				   for(int i=0;i<6;i++){
    					  System.out.println((i+1)+"\t"+students[i]+"\t"+score[i][3]);
    					  }
    				  }
    
    				  else if(course.equalsIgnoreCase("html")){
    					   System.out.println("名次    姓名    HTML");
    				 for (int i = 0; i < 6; i++){
                       for (int j = 0; j < 6 - i - 1; j++){
                        if (score[j][4] > score[j + 1][4]) {
                            m = score[j][4];
                            score[j][4] = score[j + 1][4];
                            score[j + 1][4] = m; // 分数交换
                            t = students[j];
                            students[j] = students[j + 1];
                            students[j + 1] = t; // 名字交换；//这是C的类的成绩排序
                        }
    				   }
    				 }
    				   for(int i=0;i<6;i++){
    					  System.out.println((i+1)+"\t"+students[i]+"\t"+score[i][4]);
    					  }
    				  }
    				   else{
    				        System.out.println("没有这门课程");
    				   }
    
    			  }
    			  else{
    			       System.out.println("退出查询系统！byebye!");
    				   break;
    			  }
    	 }
    }
    }

以下是运行效果的展示

![7d8ef5672a8f4e39b01a9b928ea98990.png][]

代码经过不断修改终于达到预期输出，其中仍有不足，亲多多指教。

[7d8ef5672a8f4e39b01a9b928ea98990.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/24/488740f01f6040e1a530c00b92f99bc3.png