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);
        String str =in.nextLine();//next是以空格为分隔符，nextLine是以换行符为分隔符
        String char1 = in.next();
        int count =0;
        if(Character.isLetter(char1.charAt(0))){
            Character char2 =Character.toLowerCase(char1.charAt(0));
            for(int i=0;i<str.length();i++){
                if(Character.toLowerCase(str.charAt(i)) == char2){
                    count++;
                }
            }
        }
        if(Character.isDigit(char1.charAt(0))){
            for(int i=0;i<str.length();i++){
                if(char1.charAt(0) ==str.charAt(i)){
                    count++;
                }
            }

        }
        System.out.println(count);

    }
}