Java 中的直方圖程式
Yashaswi Kothari
2021年6月29日
直方圖允許我們維護不同類別值的計數。我們也可以用圖形來表示它們。
在本文中，我們將使用 Java 建立一個直方圖，用於儲存所擲骰子的總和。
為了檢查這些值，我們將使用 if-else 階梯。if-else 階梯是一種比較一個元素和多個值的有效方法。我們在不同的整數變數中維護每個總和的計數。當匹配發生時，每個變數都會增加。
我們要求使用者輸入直方圖陣列的大小。該陣列將代表每個骰子將被擲出的總次數。然後我們將初始化作為同時投擲的兩個骰子的總和出現的數字，從 2 到 12。
使用者輸入兩個骰子的值，我們將計算它們的總和。if-else 階梯將比較不同可能性的總和，並在每次匹配發生時遞增。
我們將在以下程式中實現所有這些。
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");
}
}
輸出：
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
請注意，為了顯示最終輸出，我們建立了一個單獨的函式 toStars()，它將每種可能性的頻率轉換為星星的數量。這種方法在視覺上很吸引人，並且可以很好地表示直方圖。