如何计算字符串中的大写和小写字母? [英] How to count uppercase and lowercase letters in a string?

问题描述

哟，所以我试图制作一个程序来接收用户的字符串输入，例如:一次一次"，然后报告该字符串包含多少个大写和小写字母:

yo, so im trying to make a program that can take string input from the user for instance: "ONCE UPON a time" and then report back how many upper and lowercase letters the string contains:

输出示例:字符串具有8个大写字母 该字符串有5个小写字母，即时通讯应该使用字符串类而不是数组，有关如何开始使用该字符串的任何提示?在此先感谢，这是我到目前为止所做的:D！

output example: the string has 8 uppercase letters the string has 5 lowercase letters, and im supposed to use string class not arrays, any tips on how to get started on this one? thanks in advance, here is what I have done so far :D!

import java.util.Scanner;
public class q36{
    public static void main(String args[]){

        Scanner keyboard = new Scanner(System.in);
        System.out.println("Give a string ");
        String input=keyboard.nextLine();

        int lengde = input.length();
        System.out.println("String: " + input + "\t " + "lengde:"+ lengde);

        for(int i=0; i<lengde;i++) {
            if(Character.isUpperCase(CharAt(i))){

            }
        }
    }
}

推荐答案

简单地创建一个计数器，该计数器在找到小写或大写字母时会递增，就像这样:

Simply create counters that increment when a lowercase or uppercase letter is found, like so:

for (int k = 0; k < input.length(); k++) {
    /**
     * The methods isUpperCase(char ch) and isLowerCase(char ch) of the Character
     * class are static so we use the Class.method() format; the charAt(int index)
     * method of the String class is an instance method, so the instance, which,
     * in this case, is the variable `input`, needs to be used to call the method.
     **/
    // Check for uppercase letters.
    if (Character.isUpperCase(input.charAt(k))) upperCase++;

    // Check for lowercase letters.
    if (Character.isLowerCase(input.charAt(k))) lowerCase++;
}

System.out.printf("There are %d uppercase letters and %d lowercase letters.",upperCase,lowerCase);

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