Java 爪哇博士；为什么这不是编译？

我想知道为什么我的程序不能在Dr.Java上正确编译。我的代码有问题吗

实践测试#1

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如评论所示，我认为它是编译的。请尝试确保您的文件名与类名相同

能告诉我们错误是什么吗？你给我们看的代码是编译的。

import java.util.Scanner;

public class practest1 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in); //reads keyboard input
        System.out.println("please input a string, float or integer"); //asks the user to input into the text field.

        String twine; //names string with variable name of "twine".
        float wood; //names float with variable name of "wood".
        int maths; //names int with the variable name of "maths".


        System.out.println("Please type a string (please input words"); //asks the user to input a sting.
                           twine = sc.nextLine(); // links twine to the entered input
                           System.out.println("Thanks for entering a string" + twine); //displays twine on the screen to siqnify what the user entered


         System.out.println("Please type a float (please input decimal point number"); //asks the user to input a decimal point number.
                           wood = sc.nextFloat(); // links wood to the entered input
                           System.out.println("Thanks for entering a float" + wood); //displays wood on the screen to siqnify what the user entered 



         System.out.println("Please type a int (please input a number"); //asks the user to input a number.
                           maths = sc.nextInt(); // links maths to the entered input
                           System.out.println("Thanks for entering some integer" + maths); //displays maths on the screen to siqnify what the user entered

    }
}