题解 | #计算某字符出现次数#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
       

        // outlenghth
        Integer outlenghth = 0;
        String inputStr = in.nextLine();    
        char compaceChar = in.nextLine().charAt(0);
        
        if(null == inputStr || "".equals(inputStr)){
             System.out.println("请输入目标字符串");
             return;
        }

        if("".equals(compaceChar)){
             System.out.println("请输入比较字符");
             return;
        }

        
        String upCompaceChar = (compaceChar+"").toUpperCase();
        String lowCompaceChar = (compaceChar+"").toLowerCase();
        char[] strArr = inputStr.replaceAll(" ","").toCharArray();
        for(int i=0,len=strArr.length;i < len;i++){
  
            String tmpStr = strArr[i]+"";
            if(tmpStr.equals(upCompaceChar) || tmpStr.equals(lowCompaceChar)){
                outlenghth = outlenghth + 1;
            }
              
        }
        System.out.println(outlenghth);


    }
}