gradesystem.java

一个进行学生分数管理的小程序

import java.io.*;
public class GradeSystem {
	public static int MAXSTUDENTS = 3;
	int scores[] = new int[MAXSTUDENTS];
	int count = 0;
	public static void main(String argv[]) throws IOException{
		GradeSystem gradeSys = new GradeSystem();
		gradeSys.functionOption();
	}
	public void functionOption(){
		while(true){
			System.out.println("欢迎使用成绩管理系统");
			System.out.println("1.录入学生成绩");
			System.out.println("2.计算总成绩");
			System.out.println("3.计算平均成绩");
			System.out.println("4.成绩分析");
			System.out.println("5.退出系统");
			System.out.println("请输入数字1-5选择功能>>");
			
			int option = 1;
			try{
				option = readInteger();
			}catch(IOException e){
				e.printStackTrace();
				continue;
			}catch(NumberFormatException e){
				System.out.println("错误提示：只能输入数字1-5选择功能\n");
				continue;
			}
			switch(option){
			case 1://录入成绩
				count = inputGrades(scores);
				break;
			case 2://计算总成绩
				if(count == 0){
					System.out.println("请先录入学生成绩");
					continue;
				}
				System.out.println("学生总成绩= " + totalGrades(scores,count));
				waitPress();
				break;
			case 3://计算平均成绩
				if(count == 0){
					System.out.println("请先录入学生成绩");
					continue;
				}
				System.out.println("学生平均成绩= " + averageGrades(scores,count));
				waitPress();
				break;
			case 4://成绩分析
				if(count == 0){
					System.out.println("请先录入学生成绩");
					continue;
				}
				this.analysisGrades(scores,count);
				waitPress();
				break;
			case 5://退出系统
				return;
			default:
				System.out.println("输入数字有误，请输入1-5的数字选择功能>>");
			    waitPress();
			    break;
			}
		}
	}
	public int inputGrades(int scores[]){
		int count = 0;
		while(true){
			int grade = getAndValidateGrade();
			if(grade == -1)
				break;
			scores[count] = grade;
			count++;
			if(count >= MAXSTUDENTS){
				System.out.println("学生人数最多不能超过" + MAXSTUDENTS);
				waitPress();
				break;
			}
		}
		return count;
	}
	public int averageGrades(int scores[],int count){
		int sum = 0;
		sum = totalGrades(scores,count);
		return sum / count;
	}
	public int totalGrades(int scores[],int count){
		int sum = 0;
		for(int i = 0;i < count;i++){
			sum += scores[i];
		}
		return sum;
	}
	public void analysisGrades(int scores[],int count){
		int numberPassed = 0;
		int numberFailed = 0;
		int numberBe90_100 = 0;
		int numberBe80_90 = 0;
		int numberBe70_80 = 0;
		int numberBe60_70 = 0;
		int numberBe0_59 = 0;
		for(int i = 0;i < count;i++){
			if(scores[i] >= 60)
				numberPassed++;
			else
				numberFailed++;
			int n = (int)Math.floor(scores[i] / 10);
//			String level;
			switch(n){
			case 10:
			case 9:numberBe90_100++;
			    break;
			case 8:numberBe80_90++;
			    break;
			case 7:numberBe70_80++;
			    break;
			case 6:numberBe60_70++;
			    break;
			default:numberBe0_59++;
			    break;
			}
		}
		System.out.println("及格人数= " + numberPassed);
		System.out.println("不及格人数= " + numberFailed);
		System.out.println("等级为“优秀”人数= " + numberBe90_100);
		System.out.println("等级为“良”人数= " + numberBe80_90);
		System.out.println("等级为“中”人数= " + numberBe70_80);
		System.out.println("等级为“及格”人数= " + numberBe60_70);
		System.out.println("等级为“不及格”人数= " + numberBe0_59);
	}
	private int getAndValidateGrade(){
		int grade = 0;
		while(true){
			System.out.println("输入学生成绩如88，" + "输入-1表示结束>>");
			try{
				grade = readInteger();
			}catch(IOException e){
				System.out.println("输入成绩有误");
				e.printStackTrace();
				continue;
			}catch(NumberFormatException e){
				System.out.println("错误提示：学生成绩应该为整数且在0-100\n");
			}
			if((grade != -1)&&((grade < 0)||(grade > 100))){
				System.out.println("错误提示：学生成绩应该在0-100\n");
				continue;
			}
			else
				break;
		}
		return grade;
	}
	private int readInteger() throws IOException{
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		return Integer.parseInt(in.readLine());
	}
	private void waitPress(){
		try{
			System.out.println("按任意键继续>>");
			System.in.read();
		}catch(IOException e){}
	}
}