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try-catch语句出错

[英]Error with the try-catch statements

I need help fixing the try-catch statement so that it will handle the exception on the first try. 我需要修复try-catch语句的帮助,以便它将在第一次尝试时处理异常。 At the moment, the exception handler only works on the second user input. 目前,异常处理程序仅适用于第二个用户输入。 I apologize in advance for my terrible wording. 我为我的措辞不佳表示歉意。

class MyGradeLevels {

    public static void main(String[] args) {
         System.out.println("Please enter your grade to begin!");

         java.util.Scanner input=new java.util.Scanner(System.in); 
         double grade=input.nextInt();

         if ( grade >= 90 ) {
            System.out.println("Great Job!");
         } else if( grade <= 49 ) {
            System.out.println("Needs Improvement!");
         } else {
            System.out.println("Average Effort!");
         } 

        try { 
              grade=input.nextInt(); 
              System.out.println("Your Final Grade is "+grade); 
         } 
        catch( java.util.InputMismatchException e ) { 
              System.out.println("Please round your number and restart!"); 
         }

         input.close();     
    }
}

You already have the code written out and all. 您已经写出了全部代码。 Either start the "try" earlier, orsurround the first input with the same exact try catch: 要么更早开始“ try”,要么用完全相同的try catch包围第一个输入:

class MyGradeLevels {

    public static void main(String[] args) {
         System.out.println("Please enter your grade to begin!");

         java.util.Scanner input=new java.util.Scanner(System.in); 
         double grade;
        try { 
              grade=input.nextInt();
              if ( grade >= 90 ) {
                 System.out.println("Great Job!");
              } else if( grade <= 49 ) {
                 System.out.println("Needs Improvement!");
              } else {
                 System.out.println("Average Effort!");
              } 
         } 
        catch( java.util.InputMismatchException e ) { 
              System.out.println("Your number isn't right.");

         }

        try { 
              grade=input.nextInt(); 
              System.out.println("Your Final Grade is "+grade); 
         } 
        catch( java.util.InputMismatchException e ) { 
              System.out.println("Please round your number and restart!"); 
         }

         input.close();     
    }
}

I think this is what you want, but if not say... 我想这就是您想要的,但是如果不说...

class MyGradeLevels {

public static void main(String[] args) {
    System.out.println("Please enter your grade to begin!");
    double grade = 0;
    try {
        java.util.Scanner input = new java.util.Scanner(System.in);
        grade = input.nextInt();
    } catch (java.util.InputMismatchException e) {
        System.out.println("Please round your number and restart!");
    }
    if (grade >= 90) {
        System.out.println("Great Job!");
    } else if (grade <= 49) {
        System.out.println("Needs Improvement!");
    } else {
        System.out.println("Average Effort!");
    }

    try {
        java.util.Scanner input = new java.util.Scanner(System.in);
        grade = input.nextInt();
        System.out.println("Your Final Grade is " + grade);
        input.close();
    } catch (java.util.InputMismatchException e) {
        System.out.println("Please round your number and restart!");
    }

}
}

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