（JAVA保留小数问题，基础）Probability hdu2131

Posted 2021-01-06 PJCK

Probability

链接：http://acm.hdu.edu.cn/showproblem.php?pid=2131

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 8731    Accepted Submission(s): 4228

Problem Description

Mickey is interested in probability recently. One day , he played a game which is about probability with mini.First mickey gives a letter and a word to mini.Then mini calculate the probability that the letter appears in the word.For example,give you the letter "a" and the word "apple". the probability of this case is 0.20000.

 

Input

The input contains several test cases. Each test case consists of a letter and a word.The length of the word is no longer than 200.

 

Output

For each test case, print the probability rounded to five digits after the decimal point.

 

Sample Input

a apple

c Candy

a banana

 

Sample Output

0.20000

0.20000

0.50000

 注：

此题是java水题，注意要int与double进行转换。

 

import java.math.BigDecimal;
import java.util.Scanner;

import javax.swing.plaf.basic.BasicArrowButton;

public class Main {

    public static void main(String[] args) {
        Scanner inScanner = new Scanner(System.in);
        while(inScanner.hasNext()) {
            String string = inScanner.next();
            String string2 = inScanner.next();
            string = string.toLowerCase();
            string2 = string2.toLowerCase();
            char c = string.charAt(0);
            int number = 0;
            BigDecimal bigDecimal = BigDecimal.valueOf(0);
            for(int i = 0;i<string2.length();i++) {
                if(string2.charAt(i) == c) {
                    number ++;
                }
            }
            double number1 = number/1.0;  //int和double的转换。
            double d = number1/string2.length();
            bigDecimal = bigDecimal.add(BigDecimal.valueOf(d).setScale(5,BigDecimal.ROUND_HALF_UP)); //保留5位小数。
            System.out.println(bigDecimal);
        }
    }

}