Question

所以我真的很难格式化直方图，使它看起来像我们要做的那样。我完全迷失和沮丧，因为我不能让它看起来像所要求的相同的直方图。这是我们指令的链接，那里有一张图片，看起来像什么，我不能在这里拍照，因为我没有足够的声誉，但这里是链接：http://www.cs.plu.edu/courses/csce144/fall2013/labs/lab07/RandomNumberTesting.html 在此先感谢您的帮助！

import java.util.Scanner;   // to be able to read from the keyboard

public class RandomNum
{   
/* 
Method 1:
Find the maximun value in an array
*/
public static int max(int[]arr){
    int maxValue = arr[0];
    for ( int i=1; i < arr.length; i++ ){
        if (arr[i] > maxValue){
            maxValue = arr[i];
        }
    }
    return maxValue;
}
/* 
Method 2:
Compute a random integer in the range [a..b)
*/
public static int randomInteger(int a, int b){;
    int randomNum;

    randomNum = (int)(Math.random() * (b+1-a) + a);
    return randomNum;
}
/* 
Method 3:
Draw a Simple histogram of the array arr.
*/
public static void drawHistogram(int[] arr){
    for ( int i=max(arr); i>0; i--){
        System.out.print(i + "\t");
        for (int j=0; j<arr.length; j++){
            if ( arr[j] >= i){
                System.out.print("x");
            }else {
                System.out.print("  ");
            }if ( j%10 == 0 && j!=0){
                System.out.print("  ");
            }
        }System.out.println();
    }
    for (int i=0; i<=arr.length; i++){
        if ( i == 0){
            System.out.print("\t\t");
        }if ( i%10 == 0 && i != 0){
            System.out.print(i + "      ");
        }
    }System.out.println();  
}

/* 
Method 4:
Compute num random integers in the range [0..range) and put the frequency in arr[]
*/
public static void doSingleTest(int[] arr, int num, int range){
    for (int i=1; i<=num; i++){
        int random = randomInteger(0,range);
        arr[random]++;
    }
}
/* 
Method 5:
Compute num pairs of random integers in the range [0..range) and put the frequency in arr[]
*/
public static void doPairsTest(int[] arr, int num, int range){
    int rangeA = range/10;
    int rangeB = range%10;
    for (int i=1; i<=num; i++){
        int random = ((randomInteger(0,rangeA) * 10) + randomInteger(0,rangeB));
        arr[random]++;
    }
}
public static void main(String[] args) {

    Scanner keyboard = new Scanner(System.in);
    // declarations
    int num;
    // histogram presentation
    System.out.println("Enter the amount of pairs you want to test: ");
    num = keyboard.nextInt();
    int[] arr = new int[100];
    doPairsTest(arr, num, 99);
    drawHistogram( arr );

}

}

Answer 1

我不知道你的代码在做什么，所以我给你举个例子。假设你有20个值

int[] array = new int[20];
for (int i = 0; i < array.length; i++){
    array[i] = (int)(Math.random() * 50 + 1);  // random 1 to 50
}

首先我找到最大值;

int max = 0;
for(int i = 0; i < array.length; i++){
    if (array[i] > max) {
        max = array[i];
    }
}

然后您可以使用max值和array.length来循环输出。

for (int i = max; i >= 0; i--){  // start at the max number to print out
    // print i
    System.out.printf("%-4f", i);

    for (int j = 0; j < array.length; i++){  // remember, you're printing sideways
        if (array[j] >= i) { 
            System.out.print("x");
        } else {
            System.out.print(" "); // if condition not met, print space
        }
    }
    System.out.print("\n");
}

编辑：使用方法

public static void histogram(int[] array){
    int max = 0;
    for(int i = 0; i < array.length; i++){
        if (array[i] > max) {
            max = array[i];
        }
    }

    for (int i = max; i >= 0; i--){  // start at the max number to print out
        // print i
        System.out.printf("%-4f", i);

        for (int j = 0; j < array.length; i++){  // remember, you're printing sideways
            if (array[j] >= i) { 
                System.out.print("x");
            } else {
                System.out.print(" "); // if condition not met, print space
            }
        }
        System.out.print("\n");
    }
}

调用main方法

public static void main(String[] args){

    // your code to get your array goes here.
    int[] yourArray = // whatever your array is

    histogram(yourArray);
    // this is all you need to do, just call my method with your array
}

如何格式化直方图？

1 个答案: