public class 廖雪峰 {    public static void main(String[] args) {        Scanner scanner = new Scanner(System.in);        System.out.print("请输入上次考试成绩：");        int A = scanner.nextInt();        System.out.print("请输入本次考试的成绩：");        int B = scanner.nextInt();        float C = (float)(B - A) / A * 100;        System.out.printf("成绩提高了%.2f%%",C);    }}