嗨第一次海报和java初学者。
问题：尝试使用 gradeDistn 方法返回学生分数的计数值
gradeDistn方法将接受一个字符数组，这些字符是为标记数组指定的等级，例如grade方法返回的等级。 gradeDistn方法将返回一个整数值数组，其中包含成绩分布，即所分配成绩中每个成绩的出现次数。用于成绩的字符是固定的。返回的数组应按照从A级到F级的顺序提供分布
输出
Min是24
Max是97
范围是74
平均值为62
中位数为62
模式是53
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEEEEEDDDDDDDDDDCCCCCCCCCCCCCCCBBBBBBBBBBBBBBBAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
商标的分配
A：1
B：1
C：1
D：1
E：1
F：1
import java.util.Random;
import java.lang.Math;
import java.lang.reflect.Array;
import java.util.Arrays;
public class Marks {
private static final int NMARKS = 125;
private static final double mean = 65.0;
private static final double std = 15.0;
/**
* Returns an array of NMARKS integer marks approximately normally distributed,
* with specified mean (mean) and standard deviation (std),
* and with values outside 0..100 removed.
* @return the array of marks.
*/
public static int[] getMarks() {
Random rand = new Random(1001L);
int mark;
int[] theMarks = new int[NMARKS];
int n = 0;
while (n < NMARKS) {
mark = (int) Math.round(std*rand.nextGaussian() + mean);
if (mark >= 0 && mark <= 100)
theMarks[n++] = mark;
}
return theMarks;
}
/**
* Test code
* @param args not used
*/
public static void main(String[] args) {
int[] testMarks = getMarks();
int[] sortedMarks = arraySort (testMarks);
System.out.println("Unsorted marks\n");
for (int n = 0; n < testMarks.length; n++) {
System.out.print(testMarks[n] + " ");
if (n % 10 == 9)
System.out.println();
}
System.out.println("\n\nSorted marks\n");
for (int n = 0; n < sortedMarks.length; n++) {
System.out.print(sortedMarks[n] + " ");
if (n % 10 == 9)
System.out.println();
}
System.out.println("\n\n");
//Print Minimum
int minimum = getMin(getMarks());
System.out.println("Min is " + minimum);
//Print Maximum
int maximum = getMax(getMarks());
System.out.println("Max is " + maximum);
//Print Range
int range = (getRange(maximum, minimum));
System.out.println("Range is " + range);
//Print Mean
int mean = getMean(getMarks());
System.out.println("Mean is " + mean);
//Print Median
int median = getMedian(sortedMarks);
System.out.println("Median is " + median);
//Print Mode
int mode = getMode(sortedMarks);
System.out.println("Mode is " + mode);
//Print Grades
char[] grades = getGrades(sortedMarks);
System.out.println(grades);
//Print gradeDistn
int[] gradeDistrubution = gradeDistn(grades);
System.out.println("Distribution of Marks\nA: " + gradeDistrubution[0] + "\nB: " + gradeDistrubution[1] + "\nC: " +
gradeDistrubution[2] + "\nD: " + gradeDistrubution[3] + "\nE: " + gradeDistrubution[4] +
"\nF: " + gradeDistrubution[5]);
}
//getMin method will return the minimum mark
public static int getMin(int[] inputArray){
int minValue = inputArray[0];
for(int i=1;i < inputArray.length;i++){
if(inputArray[i] <minValue){
minValue = inputArray[i];
}
}
return minValue;
}
//getMax method will return the maximum mark
public static int getMax(int[] inputArray){
int maxValue = inputArray[0];
for(int i=1;i < inputArray.length;i++){
if(inputArray[i] > maxValue){
maxValue = inputArray[i];
}
}
return maxValue;
}
//getRange method will find the difference between the maximum and minimum marks
public static int getRange(int maxNum, int minNum){
int max = maxNum;
int min = minNum;
int range = (max - min) + 1;
return range;
}
//getMean method will return the average of marks
public static int getMean(int[] inputArray){
int total = 0;
for(int i: inputArray){
total += i;
}
return total/(inputArray.length);
}
// arraySort method sorts the array of grades in numerical ascending order
public static int [] arraySort(int [] inputArray){
int [] sortedArray = Arrays.copyOf(inputArray, inputArray.length);
Arrays.sort(sortedArray);
return sortedArray;
}
//getMedian method will return the median value of the set of marks
public static int getMedian(int[] inputArray){
int listLength = inputArray.length;
int x = listLength / 2;
int median = inputArray[x];
return median;
}
//getMode method will return the mode of the set of marks, which is the most commonly occurring mark
public static int getMode(int[] n) {
int maxValue = 0;
int maxCounts = 0;
int[] counts = new int[n.length];
for (int i=0; i < n.length; i++) {
counts[n[i]]++;
if (maxCounts < counts[n[i]]) {
maxCounts = counts[n[i]];
maxValue = n[i];
}
}
return maxValue;
}
/*grades method will return an array of characters which are the grades
corresponding to the integer marks in the array of marks */
public static char [] getGrades(int[] n){
int[] grades = new int[n.length];
char[] marks = {'A', 'B', 'C', 'D', 'E', 'F'};
char[] convertedGrades = new char[n.length];
for (int i = 0 ; i < grades.length; i++){
grades [i] = i;
if (grades[i] >= 90)
convertedGrades[i] = marks[0];
else if (grades[i] >= 75)
convertedGrades[i] = marks[1];
else if (grades[i] >= 60)
convertedGrades[i] = marks[2];
else if (grades[i] >= 50)
convertedGrades[i] = marks[3];
else if (grades[i] >= 45)
convertedGrades[i] = marks[4];
else
convertedGrades[i] = marks[5];
}
return convertedGrades;
}
// GRADESDISTN METHOD
public static int[] gradeDistn(char[] arr){
char[] characterArray = new char[arr.length];
int A=0,B=0,C=0,D=0,E=0,F=0;
for (char i = 0 ; i < characterArray.length; i++){
characterArray [i] = i;
if (characterArray[i] == 'A')
A++;
if (characterArray[i] == 'B')
B++;
if (characterArray[i] == 'C')
C++;
if (characterArray[i] == 'D')
D++;
if (characterArray[i] == 'E')
E++;
if (characterArray[i] == 'F')
F++;
}
int[] marks = {A, B, C, D, E, F};
return marks;
}
}
答案 0 :(得分：1)
int A=0,B=0,C=0,D=0,E=0,F=0;
int[] marks = {A, B, C, D, E, F};
不会将marks与A，B等联系起来。
增加A marks时保持不变。
我建议你在完成所有计算后构建marks。只需在返回前放置int[] marks = {A, B, C, D, E, F};。
PS：if (characterArray[i] == 'B') A++;对我来说不合适。
答案 1 :(得分：0)
由于@talex解释了您的代码有什么问题，我可以为您指出一个更好的解决方案：因为您的grades是字母序列，所以它们可以匹配长度为'F' - 'A' + 1的数组（数量为'A'和'F'之间的字母。匹配函数将尽可能简单：使用grade - 'A'作为数组的索引，使用i + 'A'作为恢复函数。