0. 目录
- 一个程序搞定成绩的各种处理需求
1. 一个程序搞定成绩的各种处理需求
- 求某年最好成绩
- 求某年的平均成绩
- 求所有年份最好成绩
- 求某门课历年最好成绩
- 自由发挥……
/**
* @ClassName: ScoreMaster
* @Description: TODO
* @Author: AI悦创
* @Date: 2022/10/9 19:24
* @Version: V1.0
* @Blog: https://www.bornforthis.cn
*/
import java.util.Scanner;
public class ScoreMaster {
public static void main(String[] args) {
// 声明六个变量, 分别代表六门科目的成绩
int YuWenIndex = 0;
int ShuXueIndex = 1;
int WaiYuIndex = 2;
int WuLiIndex = 3;
int HuaXueIndex = 4;
int ShengWuIndex = 5;
int totalScoreCount = 6;
// 每门课的名字
String[] names = new String[totalScoreCount];
names[YuWenIndex] = "语文";
names[ShuXueIndex] = "数学";
names[WaiYuIndex] = "外语";
names[WuLiIndex] = "物理";
names[HuaXueIndex] = "化学";
names[ShengWuIndex] = "生物";
Scanner scanner = new Scanner(System.in);
System.out.println("请输入共有多少年的成绩:");
int yearCount = scanner.nextInt();
double[][] scores = new double[yearCount][totalScoreCount]; // 看几年的数组
for (int i = 0; i < yearCount; i++) {
for (int j = 0; j < totalScoreCount; j++) {
scores[i][j] = 80 + Math.random() * 20;
System.out.println("第" + (i + 1) + "年" + names[j] + "成绩为:" + scores[i][j]);
}
}
boolean cont = true;
while (cont) {
System.out.println("请选择要进行的操作:");
System.out.println("1: 求某年最好成绩\n" +
"2: 求某年的平均成绩\n" +
"3: 求所有年份最好成绩\n" +
"4: 求某门课历年最好成绩");
int oprtId = scanner.nextInt();
int year = 0; // 在 switch 用一块代码块里,不能声明同一个变量,所以直接写在外面,方便。不然得想不同的变量名。
switch (oprtId) {
// 先编写 case
case 1:
// 让用户输入指定的年份
System.out.println("请输入要计算第几年的最好成绩");
year = scanner.nextInt();
if (year <= 0 || yearCount < year) {
System.out.println("非法的年份:" + year);
cont = false;
break;
}
year = year - 1;
// 指定年份的最好成绩的编号,开始假设是0
int bestOfYearScoreId = 0;
// 循环指定年份的成绩,找出最好的成绩
// TODO:如果有两门课的成绩一样,而且都是最高的,怎么办?
for (int i = 1; i < totalScoreCount; i++) {
if (scores[year][bestOfYearScoreId] < scores[year][i]) {
bestOfYearScoreId = i;
}
}
System.out.println("第" + (year + 1) + "年成绩最好的科目为" + names[bestOfYearScoreId] + ",成绩为" + scores[year][bestOfYearScoreId] + "。");
break;
case 2:
System.out.println("请输入要计算第几年的平均成绩");
year = scanner.nextInt();
if (year <= 0 || yearCount < year) {
System.out.println("非法的年份:" + year);
cont = false;
break;
}
year = year - 1;
double totalCountForAvg = 0;
for (int i = 0; i < totalScoreCount; i++) {
totalCountForAvg += scores[year][i];
}
double avgOfYear = totalCountForAvg / totalScoreCount;
System.out.println("第" + (year + 1) + "年的平均成绩为" + avgOfYear + "。");
break;
case 3:
int bestYear = 0;
int bestScore = 0;
for (int i = 0; i < yearCount; i++) {
for (int j = 0; j < totalScoreCount; j++) {
if (scores[bestYear][bestScore] < scores[i][j]) {
bestYear = i;
bestScore = j;
}
}
}
// 视频中代码有错误,应该是使用 bestYear 而不是 year, 鸣谢 @zZGod 帮忙揪出 bug 一只。
System.out.println("所有年度最好成绩为第" + (bestYear + 1) + "年的" + names[bestScore] + ",成绩为" + scores[bestYear][bestScore] + "。");
break;
case 4:
System.out.println("请输入科目编号");
int subjectId = scanner.nextInt();
if (subjectId <= 0 || totalScoreCount < subjectId) {
System.out.println("非法的科目编号:" + subjectId);
cont = false;
break;
}
subjectId = subjectId - 1;
year = 0;
for (int i = 1; i < yearCount; i++) {
if (scores[year][subjectId] < scores[i][subjectId]) {
year = i;
}
}
System.out.println("第" + (year + 1) + "年度" + names[subjectId] + "成绩最好,为" + scores[year][subjectId] + "。");
break;
default:
cont = false;
System.out.println("不支持:" + oprtId + ", 程序结束。");
}
}
}
}
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