public class Main {

public static void main(String[] args) {

System.out.println("请输入上次考试成绩：");

Scanner scanner = new Scanner(System.in);//创建scanner对象

int prev = scanner.nextInt();

System.out.println("请输入本次考试成绩");

int score = scanner.nextInt();

double improve = (double)(score-prev)/prev*100;

System.out.printf("成绩较上次提高百分比为%.2f%%",improve);

//格式化输出%%表示%，以防识别错误。double型在输出的时候写%f

}