Java 中的直方图程序
Yashaswi Kothari
2021年6月29日
直方图允许我们维护不同类别值的计数。我们也可以用图形来表示它们。
在本文中，我们将使用 Java 创建一个直方图，用于存储所掷骰子的总和。
为了检查这些值，我们将使用 if-else 阶梯。if-else 阶梯是一种比较一个元素和多个值的有效方法。我们在不同的整数变量中维护每个总和的计数。当匹配发生时，每个变量都会增加。
我们要求用户输入直方图数组的大小。该数组将代表每个骰子将被掷出的总次数。然后我们将初始化作为同时投掷的两个骰子的总和出现的数字，从 2 到 12。
用户输入两个骰子的值，我们将计算它们的总和。if-else 阶梯将比较不同可能性的总和，并在每次匹配发生时递增。
我们将在以下程序中实现所有这些。
import java.io.*;
class Main
{
public static String toStars(int number) {
StringBuilder temp = new StringBuilder();
for(int i=0;i<number;i++) {
temp.append("*");
}
return temp.toString();
}
public static void main(String[] args)throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.print("Total rolls for each dice?");
int n = Integer.parseInt(br.readLine());
int [] rolls = new int[n];
int d1;
int d2;
int two = 0;
int three = 0;
int four = 0;
int five = 0;
int six = 0;
int seven = 0;
int eight = 0;
int nine = 0;
int ten = 0;
int eleven = 0;
int twelve = 0;
for (int roll=0; roll < rolls.length; roll++)
{
System.out.println("First dice roll");
d1 = Integer.parseInt(br.readLine());
System.out.println("Second dice roll");
d2 = Integer.parseInt(br.readLine());
System.out.println(" The first dice rolled a " + d1 + " the second dice rolled a " + d2);
int sum;
sum = d1 + d2;
if (sum == 2)
two++;
if (sum == 3)
three++;
if (sum == 4)
four++;
if (sum == 5)
five++;
if (sum == 6)
six++;
if (sum == 7)
seven++;
if (sum == 8)
eight++;
if (sum == 9)
nine++;
if (sum == 10)
ten++;
if (sum == 11)
eleven++;
if (sum == 12)
twelve++;
}
System.out.println("Histogram of rolls:" );
System.out.println("2 occurred " + toStars(two) + " times");
System.out.println("3 occurred " + toStars(three) + " times");
System.out.println("4 occurred " + toStars(four) + " times");
System.out.println("5 occurred " + toStars(five) + " times");
System.out.println("6 occurred " + toStars(six) + " times");
System.out.println("7 occurred " + toStars(seven) + " times");
System.out.println("8 occurred " + toStars(eight) + " times");
System.out.println("9 occurred " + toStars(nine) + " times");
System.out.println("10 occurred " + toStars(ten) + " times");
System.out.println("11 occurred " + toStars(eleven) + " times");
System.out.println("12 occurred " + toStars(twelve) + " times");
}
}
输出：
Total rolls for each dice?5
First dice roll
1
Second dice roll
2
The first dice rolled a 1 the second dice rolled a 2
First dice roll
2
Second dice roll
1
The first dice rolled a 2 the second dice rolled a 1
First dice roll
5
Second dice roll
4
The first dice rolled a 5 the second dice rolled a 4
First dice roll
1
Second dice roll
1
The first dice rolled a 1 the second dice rolled a 1
First dice roll
3
Second dice roll
1
The first dice rolled a 3 the second dice rolled a 1
Histogram of rolls:
2 occurred * times
3 occurred ** times
4 occurred * times
5 occurred times
6 occurred times
7 occurred times
8 occurred times
9 occurred * times
10 occurred times
11 occurred times
12 occurred times
请注意，为了显示最终输出，我们创建了一个单独的函数 toStars()，它将每种可能性的频率转换为星星的数量。这种方法在视觉上很吸引人，并且可以很好地表示直方图。