有人可以告诉我为什么我的代码没有提供正确的输出吗？这里是说明“
我需要编写一个程序来读取学生的分数，并获得最佳成绩 得分，然后根据以下方案分配成绩：
1）如果分数> =最佳-10
，则等级为A。2）如果分数> =最佳-20，则成绩为B；
3）如果分数> =最佳-30，则成绩为C；
4）如果分数> =最佳-40，则成绩为D；
5）否则成绩为F。
该程序提示用户输入学生总数，然后提示用户输入所有分数，并通过显示成绩得出结论。我的问题来自从数组中获得成绩，这就是我到目前为止所掌握的：
// Here is my code. Thank You
import java.util.Scanner; // imports the scanner function
public class NBpractice { //class is formed
public static void main(String []args) { // main method
// user input is asked for the number of students
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of students: ");
int studentNum = input.nextInt();
//user input is asked for students scores
Scanner input2 = new Scanner(System.in);
System.out.print("Enter " + studentNum + " scores: ");
int scores = input2.nextInt();
int best = 80;
char letterGrade;
int scoresArray[] = new int[studentNum]; // array is created and holds the # of place values as students
for (int i = 0; i < scoresArray.length; i++) { // for loop created
scoresArray[i] = input2.nextInt(); //array values are assigned to user's input
best = scoresArray[0];
if (best < scoresArray[i]) {
best = scoresArray[i];
}
//-----------------------------------------------------------------------------
if (scores >= (best - 10)) {
letterGrade = 'A';
}
else if (scores >= (best - 20)) {
letterGrade = 'B';
}
else if (scores
>= (best - 30)) {
letterGrade = 'C';
}
else if (scores >= (best - 30)) {
letterGrade = 'D';
}
else {
letterGrade = 'F';
}
System.out.println("Student " + i + " Score is " + scoresArray[i] + " and grade is: " + letterGrade );
}
//------------------------------------------------------------
}
}
答案 0 :(得分：1)
一些指针...
System.out.print("Enter " + studentNum + " scores: ");和int scores = input2.nextInt();需要进入for循环主体。for循环填充数组。for循环后，在数组中找到best（最高）分数。for循环对成绩进行排序。按原样，您的程序只会要求成绩，并且几乎都假设最佳成绩为80，但情况并非总是如此。
答案 1 :(得分：0)
您将需要两个单独的for循环。一种是阅读成绩并获得最佳成绩，另一种是for循环以标准化成绩。
int[] scores = new int[amount];
int best = -1;
for(int i = 0; i < amount; i++)
{
scores[i] = in.nextInt();
if(scores[i] > best)
best = scores[i];
}
System.out.println(Arrays.toString(scores));
// Now that we have the best, we can normalize
// the rest of the scores based on the best
// and assign the corresponding letter grade.
String[] grades = new String[amount];
for(int i = 0; i < amount; i++)
{
int score = scores[i] * 100 / best;
if(score >= 90)
grades[i] = "A";
else if(score >= 80)
grades[i] = "B";
else if(score >= 70)
grades[i] = "C";
else if(score >= 60)
grades[i] = "D";
else
grades[i] = "F";
scores[i] = score;
}
System.out.println(Arrays.toString(scores));
System.out.println(Arrays.toString(grades));
测试输入80 60 75 83 67的输出：
[80, 60, 75, 83, 67]
[96, 72, 90, 100, 80]
[A, C, A, A, B]
答案 2 :(得分：0)
我建议您使用学生班级，而不适合parallel lists or arrays使用。例如，一个学生班级可能看起来像这样：
class Student {
int score;
String grade; // could also be an Enum
public int getScore() {
return this.score;
}
public void setScore(int score) {
this.score = score;
}
public String getGrade() {
return this.grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Student{" + "score=" + score + ", grade='" + grade + '\'' + '}';
}
}
然后您可以创建学生实例，并将其添加到public static void main中的ArrayList中。
我认为您必须使用两个循环，因为您无法事先知道最佳成绩。在您的主菜单中，可以输入学生，将他们添加到List并比较他们的成绩；
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of students: ");
int highScore = 0;
int numOfStudent = input.nextInt();
List<Student> studentList = new ArrayList<>();
for (int i = 1; i <= numOfStudent; i++) { // you might want to add Exception handling here, by surrounding it with a try / catch or do more checks than only i <= numOfStudent
System.out.printf("please fill in the score of student no %d \n", i);
int score = input.nextInt();
Student student = new Student();
student.setScore(score);
if (score > highScore) {
highScore = score;
}
studentList.add(student);
}
System.out.println("these are the scores and grades of the Students");
for (Student s : studentList) {
if (s.getScore() >= highScore - 10) {
s.setGrade("A");
}
else if (s.getScore() >= highScore - 20) {
s.setGrade("B");
}
else if (s.getScore() >= highScore - 30) {
s.setGrade("C");
}
else if (s.getScore() >= highScore - 40) {
s.setGrade("D");
}
else {
s.setGrade("F");
}
System.out.println(s);
}
}
答案 3 :(得分：0)
第7章软件包
导入java.util.Scanner;
公共课程Exercise7_1 {
public static void main(String[] args) {
// Assign grades
Scanner input = new Scanner(System.in);
int numStudents;
int[] scores;
int best;
System.out.println("Enter the number of students: ");
numStudents = input.nextInt();
scores = new int[numStudents];
System.out.println("Enter " + numStudents + " scores: ");
for (int i = 0; i < numStudents; i++) {
scores[i] = input.nextInt();
}
displayGrades(findBestScore(scores), scores);
}
public static int findBestScore(int[] scores) {
int best = scores[0];
for (int i = 1; i < scores.length-1; i++) {
if (scores[i] > best)
best = scores[i];
}
return best;
}
public static void displayGrades(int best, int[] scores ) {
char grade = ' ';
for (int i = 0; i < scores.length; i++) {
if (scores[i] >= best-10)
grade = 'A';
else if (best - 10 > scores[i] && scores[i] >= best - 20)
grade = 'B';
else if (best - 20 > scores[i] && scores[i] >= best -30)
grade = 'C';
else if (best - 30 > scores[i] && scores[i] >= best -40)
grade = 'D';
else if (best - 40 > scores[i])
grade = 'F';
System.out.println("Student " + i + " score is " + scores[i] + " and grade is " + grade);
}
}
}