求助：如何为Java统计程序添加1-50数值区间的直方图功能？

Hey there! Let's get your histogram working properly, and while we're at it, fix the mode method too (it wasn't actually finding the most frequent number yet). Here's a breakdown of what was off with your current code and a fully working solution:

Issues in Your Original Code #

First, let's go over the problems in your existing graph method:

• You were modifying the original array with arr[i]++, which corrupts your input data for other calculations
• The logic for checking intervals was mixed in a single loop, meaning you weren't grouping counts by each range correctly
• Only two intervals were being handled, not all ranges from 1-5 up to 46-50
• Your mode method just returned the first element of the array, not the most frequent value

Fully Corrected Code #

Here's the complete, working program with all features (including the histogram) fixed:

import java.util.Scanner;

public class NumberStats {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        
        System.out.println("Enter the amount of numbers you would like to enter: ");
        int amount = scan.nextInt();
        int[] arr = new int[amount];
        
        for (int i = 0; i < arr.length; i++) {
            System.out.println("Enter a number 1 through 50");
            int outcome = scan.nextInt();
            // Validate input to ensure it's within 1-50
            while (outcome < 1 || outcome > 50) {
                System.out.println("Invalid number! Please enter a number between 1 and 50:");
                outcome = scan.nextInt();
            }
            arr[i] = outcome;
        }

        System.out.println("\nThe average is:");
        System.out.println(average(arr));
        System.out.println("\nThe lowest value in the array is:");
        System.out.println(min(arr));
        System.out.println("\nThe largest value in the array is:");
        System.out.println(max(arr));
        System.out.println("\nThe most frequent number in the array is:");
        System.out.println(mode(arr));
        System.out.println("\nHistogram:");
        graph(arr);
        
        scan.close();
    }

    public static double average(int[] arr) {
        double sum = 0;
        for (int num : arr) {
            sum += num;
        }
        return sum / arr.length;
    }

    public static int max(int[] arr) {
        int max = arr[0];
        for (int num : arr) {
            if (num > max) {
                max = num;
            }
        }
        return max;
    }

    public static int min(int[] arr) {
        int min = arr[0];
        for (int num : arr) {
            if (num < min) {
                min = num;
            }
        }
        return min;
    }

    public static int mode(int[] arr) {
        int mode = arr[0];
        int maxCount = 0;
        
        for (int num : arr) {
            int count = 0;
            for (int compareNum : arr) {
                if (compareNum == num) {
                    count++;
                }
            }
            if (count > maxCount) {
                maxCount = count;
                mode = num;
            }
        }
        return mode;
    }

    public static void graph(int[] arr) {
        // Define interval parameters: start at 1, each interval is 5 numbers
        int intervalSize = 5;
        int start = 1;
        
        // Loop through all intervals from 1-5 up to 46-50
        while (start <= 50) {
            int end = start + intervalSize - 1;
            // Cap end at 50 to avoid going over
            end = Math.min(end, 50);
            
            // Count how many numbers fall into this interval
            int count = 0;
            for (int num : arr) {
                if (num >= start && num <= end) {
                    count++;
                }
            }
            
            // Print the interval label and corresponding asterisks
            System.out.printf("%d - %d: ", start, end);
            for (int i = 0; i < count; i++) {
                System.out.print("*");
            }
            // Add space between intervals for readability
            System.out.print(" ");
            
            // Move to next interval
            start += intervalSize;
        }
    }
}

Key Improvements Explained #

1. Input Validation: Added a loop to ensure users only enter numbers between 1 and 50, so your data stays consistent
2. Fixed Mode Method: Now it actually counts occurrences of each number and returns the one with the highest frequency
3. Proper Histogram Logic:
   • Uses a loop to generate each interval dynamically (no hardcoding all 10 intervals manually)
   • Counts numbers per interval without modifying the original array
   • Prints each interval's label followed by the correct number of * characters, matching the format you wanted
4. Cleaner Code: Used enhanced for-loops (for (int num : arr)) where possible to make the code more readable

Example Output #

If you input numbers that match your sample expected output, the histogram will look exactly like this:

1 - 5: **** 6 - 10: ****** 11 - 15: ** 16 - 20: ********** 21 - 25: *********** 26 - 30: ******** 31 - 35: **** 36 - 40: ******* 41 - 45: ************ 46 - 50: ***************** 

内容的提问来源于stack exchange，提问作者calvin jackson