java我的代码哪里出错了？

Question

编辑：

我想我抄错了一点代码

public class GradeCalculator {

 public static void calculateGrade(int mark) {
  if (mark >= 70) System.out.println("grade = A");
  if (mark >= 60) System.out.println("grade = B");
  if (mark >= 50) System.out.println("grade = C");
  if (mark >= 40) System.out.println("grade = D");
  if (mark <  40) System.out.println("grade = F");
 }

 public static void main(String[] args) {

 }
}

我才刚刚开始尝试Java（或任何编程）。我正在练习问题。我有这段代码，需要在main方法中编写语句来测试它

我该怎么做

感谢您的帮助/指点

马克

Answer 1

为了使你的代码工作，你需要调用你的方法，因为你的所有编码都是在那部分完成的，即根据条件打印

public class GradeCalculator { // This is your class

     public static void calculateGrade(int mark) { 
  //This is the method containing conditions
    on the basis of these conditions the corroesponding
   sentences will be  printed
      if (mark >= 70) System.out.println("grade = A");
      if (mark >= 60) System.out.println("grade = B");
      if (mark >= 50) System.out.println("grade = C");
      if (mark >= 40) System.out.println("grade = D");
      if (mark <  40) System.out.println("grade = F");
     }
    //now u need to call the method from your main method.. main method is the entry point of your program so it will start from main then check your method call and do as per the code written there
     public static void main(String[] args) {
    // to call your method just right your method name and enter marks

    calculateGrade(50); // you can enter any integer 
     }
    }

Answer 2

好吧，为了开始这场闹剧，让我们把你的代码编辑成一种能够以感性的方式编译和工作的东西：

public class GradeCalculator {

    public static void claculateGrade (int mark) {
        if (mark >= 70) System.out.println("grade = A");
        else if (mark >= 60) System.out.println("grade = B");
        else if (mark >= 50) System.out.println("grade = C");
        else if (mark >= 50) System.out.println("grade = D");
        else if (mark >= 40) System.out.println("grade = E");    
    }

    public static void main (String[] args)  {

    }

}

现在，要打印一些人会得到的分数，你可以这样称呼你的“claculateGrade”方法：

public static void main (String[] args)  {
    claculateGrade(55);
}

这将在控制台上打印“grade=C”。完整代码：

public class GradeCalculator {

    public static void claculateGrade (int mark) {
        if (mark >= 70) System.out.println("grade = A");
        else if (mark >= 60) System.out.println("grade = B");
        else if (mark >= 50) System.out.println("grade = C");
        else if (mark >= 50) System.out.println("grade = D");
        else if (mark >= 40) System.out.println("grade = E");    
    }

    public static void main (String[] args)  {
        claculateGrade(55);
    }

}

现在，我们可以进一步改进这一点。让我们先让方法返回等级：

public static char getGrade (int mark) {
    if (mark >= 70) return 'A';
    else if (mark >= 60) return 'B';
    else if (mark >= 50) return 'C';
    else if (mark >= 50) return 'D';
    else if (mark >= 40) return 'E';

    /* if below 40, return "fail" */
    return 'F';
}

这会将您的代码更改为：

public class GradeCalculator {

    public static char getGrade (int mark) {
        if (mark >= 70) return 'A';
        else if (mark >= 60) return 'B';
        else if (mark >= 50) return 'C';
        else if (mark >= 50) return 'D';
        else if (mark >= 40) return 'E';

        /* if below 40, return "fail" */
        return 'F';
    }

    public static void main (String[] args)  {
        System.out.println("Grade: " + getGrade(55));
    }

}