统计字符次数

Scanner sc = new Scanner(System.in);

System.out.println("请输入一个字符串：");
String line = sc.nextLine();

int smallCount = 0;
int bigCount = 0;
int numberCount = 0;

for (int i = 0; i < line.length(); i++) {
    char ch = line.charAt(i);

    if (ch >= 'a' && ch <= 'z') {
        smallCount++;
    } else if (ch >= 'A' && ch <= 'Z') {
        bigCount++;
    } else if (ch >= '0' && ch <= '9') {
        numberCount++;
    }
}

System.out.println("大写字母个数：" + bigCount);
System.out.println("小写字母个数：" + smallCount);
System.out.println("数字个数：" + numberCount);