java - 方法/打印随机数的直方图

Question

You will develop a program to count the number of times each number in the range is generated. Your program will generate 100 numbers in the range [0, 9] and you will print a histogram similar to the histogram shown below.

 0  ********
 1  *********** 
 2  ******
 3  ****************
 4  **************
 5  *****
 6  ************
 7  ***********
 8  ********
 9  ********* 

To print the histogram shown above, your program must record the number of times each number is generated.

我试图将 num 和 count 传递到 print 方法中，然后将其传递到 switch 语句以将其打印为星号。但这给了我一个错误。建议？

这是我收到的错误:

required: int,int found: no arguments reason: actual and formal argument lists differ in length /tmp/java_9JsuaS/RandomSrv.java:55: error: method print in class RandomSrv cannot be applied to given types; System.out.print("9 " + this.print()); ^

import java.util.Random;

public class RandomSrv
{

    public void genNums(int total)
    {

        for(int counter = 0; counter < total; counter++) //counter for the random gen nums//

        {
            int UPPER_BOUND = 10;//max number it will go to: 9

            int count0 = 0; //stores counter//

            int count1 = 0;
            int count2 = 0;

            int count3 = 0;

            int count4 = 0;

            int count5 = 0;

            int count6 = 0;

            int count7 = 0;

            int count8 = 0;

            int count9 = 0;

            int count = 0;

            Random randObj = new Random(); //creating randoms object//
            int num = randObj.nextInt(UPPER_BOUND);//num ranges 1-10//
            print(num, count);
            switch (num) //counts it into catagories//
                {
                case 0: count = count0++;
                    System.out.print("0 " + this.print());
                    break;
                case 1: count = count1++;
                    System.out.print("1 " + this.print());
                    break;
                case 2: count = count2++;
                    System.out.print("2 " + this.print());
                    break;
                case 3: count = count3++;
                    System.out.print("3 " + this.print());
                    break;
                case 4: count = count4++;
                    System.out.print("4 " + this.print());
                    break;
                case 5: count = count5++;
                    System.out.print("5 " + this.print());
                    break;
                case 6: count = count6++;
                    System.out.print("6 " + this.print());
                    break;
                case 7: count = count7++;
                    System.out.print("7 " + this.print());
                    break;
                case 8: count = count8++;
                    System.out.print("8 " + this.print());
                    break;
                case 9: count = count9++;
                    System.out.print("9 " + this.print());
                    break;
                }

        }
    }
    public void print(int num, int count) //converting them to astericks//
    {
    for(int x = 0; x < count; x++)
        {
        System.out.println("*");
        }       
    }
}

Answer 1

这是一种方法:

int[] counts = new int[10];   // this array will hold the count for each number (0-9)
Random rand = new Random();   // the Random object

/* Loop 100 times getting a random number each time, and add to the corresponding count */
for(int i=0; i<100; i++)
{
    switch(rand.nextInt(10))
    {
        case 0: counts[0]++; break;
        case 1: counts[1]++; break;
        case 2: counts[2]++; break;
        case 3: counts[3]++; break;
        case 4: counts[4]++; break;
        case 5: counts[5]++; break;
        case 6: counts[6]++; break;
        case 7: counts[7]++; break;
        case 8: counts[8]++; break;
        case 9: counts[9]++; break;
        default: break;
    }
}

/* Loop 10 times printing the asterisks for each count */
for(int i=0; i<10; i++)
{
     System.out.print(i + " ");
     for(int j=0; j<counts[i]; j++)
         System.out.print("*");
     System.out.println();
}

在这里运行它(在线编译器):http://rextester.com/UKSB96871