题解 | #截取字符串#

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        if(scan.hasNext()){
            String str=scan.nextLine();  //相当于开辟了两段空间
            int num = scan.nextInt();   //nextInt()  将输入的信息的下一个标记扫面为int
            System.out.print(str.substring(0,num));
        }
        scan.close();
    }
}