1、头文件、定义函数、输出字符串、对变量赋值；定义输入的分数为“mark”，且分数会有小数
import java.util.Scanner;//头文件
class Mark{
public static void main(String[] args){
System.out.println("请输入一个分数");double mark;
Scanner scanner = new Scanner(System.in);
mark = scanner.nextDouble();
2、判断是否有输入错误。
if(mark<0||mark>100){
System.out.println("输入有误！ ");
System.exit(0);
}
3、判断分数的等级
90以上A， 80~89B，70~79分C，60~69D，60以下E
if (mark>=90) System.out.println("this mark is grade \'A\' ");
else if (mark>=80) System.out.println("this mark is grade \'B\' ");
else if (mark>=70) System.out.println("this mark is grade \'C\' ");
else if (mark>=60) System.out.println("this mark is grade \'D\' ");
else System.out.println("this mark is grade \'E\' ");
4、完整代码
import java.util.Scanner;
class Mark{
public static void main(String[] args){
System.out.println("请输入一个分数");
double mark;
Scanner scanner = new Scanner(System.in);
mark = scanner.nextDouble();
if(mark<0||mark>100){
System.out.println("输入有误！ ");
System.exit(0);
}
if (mark>=90) System.out.println("this mark is grade \'A\' ");
else if (mark>=80) System.out.println("this mark is grade \'B\' ");
else if (mark>=70) System.out.println("this mark is grade \'C\' ");
else if (mark>=60) System.out.println("this mark is grade \'D\' ");
else System.out.println("this mark is grade \'E\' ");
}
}