成績查詢類小程式

成績查詢類小程式

import java.util.Scanner;

public class array {
    public static void main(String[] args) {

        int yuWen = 0;
        int shuXue = 1;
        int waiYu = 2;
        int wuLi = 3;
        int huaXue = 4;
        int shengWu = 5;

        //定義總共課程門數，如有需要可以修改為從鍵盤獲取并將科目名字陣列通過鍵盤獲取
        int totalScoreCount = 6;

        //定義課程名字陣列并賦值
        String[] scoreNames = new String[totalScoreCount];
        scoreNames[yuWen] = "語文";
        scoreNames[shuXue] = "數學";
        scoreNames[waiYu] = "外語";
        scoreNames[wuLi] = "物理";
        scoreNames[huaXue] = "化學";
        scoreNames[shengWu] = "生物";

        Scanner in = new Scanner(System.in);
        System.out.println("請問你要保存幾年的成績？");
        int yearToStore = in.nextInt();

        //定義分數二維陣列，包含年份和科目資訊
        double[][] score = new double[yearToStore][totalScoreCount];

        //通過亂數為每年每門課賦值并輸出
        for (int i = 0; i < yearToStore; i++) {
            for (int j = 0; j < totalScoreCount; j++) {
                score[i][j] = Math.random() * 20 + 80;
                System.out.println("第" + (i + 1) + "年的" + scoreNames[j] + "成績是：" + score[i][j]);
            }
        }


        //求最大成績和索引
        /*
        double maxScore = 0;
        int maxScoreIdex = -1;
        for (int i = 0; i < totalScoreCount; i++) {
            if (score[i] > maxScore) {
                maxScore = score[i];
                maxScoreIdex = i;
            }
        }
        System.out.println("最高成績的科目是："+scoreNames[maxScoreIdex]+"\t成績為："+maxScore);

         */

        boolean start = true;
        while (start) {

            int optID;

            System.out.println("請選擇要進行的操作：");
            System.out.println("1: 求某年最好成績\n" + "2: 求某年的平均成績\n" + "3: 求所有年份最好成績\n" + "4: 求某年某門課的最好成績\n" + "5: 求某門課歷年最好成績");

            optID = in.nextInt();

            switch (optID) {
                case 1:

                    int seleYear;
                    double bestScore = 0;
                    int bestNumScore = 0;

                    System.out.println("請問你要求那年的最好成績？");
                    seleYear = in.nextInt();

                    //輸入檢查
                    if (seleYear <= 0 || seleYear > yearToStore) {
                        System.out.println("輸入年份不合法，請輸入[1," + yearToStore + "]之間的年份");
                        continue;
                    }
                    for (int i = 0; i < totalScoreCount; i++) {

                        if (score[seleYear - 1][i] > bestScore) {
                            bestScore = score[seleYear][i];
                            bestNumScore = i;
                        }
                    }
                    System.out.println("第" + seleYear + "年最好成績是：" + scoreNames[bestNumScore] + ",為" + bestScore);
                    break;
                case 2:
                    seleYear = 0;
                    double averYearScore;
                    double totalScore = 0;
                    System.out.println("請問你想要求那一年的平均成績？");
                    seleYear = in.nextInt();
                    //輸入值合法性檢查
                    if (seleYear <= 0 || seleYear > yearToStore) {
                        System.out.println("輸入年份不合法，請輸入[1," + yearToStore + "]之間的年份");
                        continue;
                    }
                    //使用foreach回圈替換
                    /*
                    for (double x:

                         score[seleYear]) {
                        totalScore+=x;
                    }
                    */


                    for (int i = 0; i < scoreNames.length; i++) {
                        totalScore += score[seleYear - 1][i];
                    }


                    averYearScore = totalScore / scoreNames.length;


                    System.out.println("第" + seleYear + "年的平均成績是：" + averYearScore);


                    break;
                case 3:


                    int maxScoreYear = 0;
                    String maxScoreName = "0";
                    double maxScore = 0;


                    for (int i = 0; i < yearToStore; i++) {
                        for (int j = 0; j < scoreNames.length; j++) {
                            if (score[i][j] > maxScore) {
                                maxScore = score[i][j];
                                maxScoreYear = i + 1;
                                maxScoreName = scoreNames[j];
                            }

                        }
                    }
                    System.out.println("第" + maxScoreYear + "年" + maxScoreName + "成績最高，成績為：" + maxScore);

                    //通過foreach回圈嵌套得出最大分數，但無法得知哪一年和哪門課程，故剔除
                    /*
                    for (double[] i:
                         score) {
                        for (double j:
                             i) {
                            if(j>maxScore){
                                maxScore = j;


                            }
                        }
                    }



                    System.out.println(maxScore);

                     */
                    break;
                case 4:

                    maxScoreYear = 0;
                    maxScore = 0;
                    maxScoreName = "0";
                    int seleName;
                    //將i定義在回圈外面，避免回圈程序中被重置
                    int y = 1;


                    System.out.println("請問你要求哪門課程的歷年最好成績？");
                    for (String x :
                            scoreNames) {

                        //按順序輸出課程并在前面加序號，每次執行后累加
                        System.out.println(y + ":" + x);
                        y++;
                    }

                    seleName = in.nextInt();

                    //合法性檢查
                    if (seleName <= 0 || seleName > scoreNames.length) {
                        System.out.println("輸入課程編號不合法，請輸入[1," + scoreNames.length + "]之間的年份");
                        continue;
                    }

                    for (int i = 0; i < score.length; i++) {
                        if (score[i][seleName - 1] > maxScore) {
                            maxScore = score[i][seleName - 1];
                            maxScoreYear = i + 1;
                            maxScoreName = scoreNames[seleName - 1];
                        }
                    }
                    System.out.println(maxScoreName + "成績最好的一次是第" + maxScoreYear + "年的" + maxScore);
                    break;
                case 5:

                    int year;
                    int num = 1;

                    System.out.println("請問你要查看第幾年的成績?");
                    year = in.nextInt() - 1;

                    //合法性檢查
                    if (year <= 0 || year > yearToStore) {
                        System.out.println("輸入年份不合法，請輸入[1," + yearToStore + "]之間的年份");
                        continue;
                    }
                    System.out.println("請問你要查看第幾門課程？");

                    //同理，得出序號
                    for (String a : scoreNames) {

                        System.out.println(num + ":" + a);
                        num++;
                    }

                    int numScore = in.nextInt() - 1;

                    if (numScore <= 0 || numScore > scoreNames.length) {
                        System.out.println("輸入課程編號不合法，請輸入[1," + scoreNames.length + "]之間的年份");
                        continue;
                    }

                    System.out.println("第" + (year + 1) + "年的" + scoreNames[numScore] + "成績是：" + score[year][numScore]);

                    break;


                default:
                    System.out.println("非法數字，程式結束！");
                    start = false;
                    //有無作用相同,單純break跳出仍會進入回圈
                    //break;
            }
        }


    }
}