Question

import java.util.*;

public class xArrays {
    public static double total;
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
       double[] marks = new double[5];
       for (int i =0;i<5;i++){
           System.out.printf("Enter your marks for course %d : ",(i+1));
          try { input.nextDouble();}
           catch ( InputMismatchException e ){
               System.out.println("this doesn't work");
               input.next();
               continue;}
           marks[i] = input.nextDouble();

           total += marks[i];




       }

我想问问标记1，然后移到标记2，但它要做的是问问标记1，我输入标记1，然后必须输入另一个数字才能继续。

Answer 1

您没有将用input.nextDouble()读取的输入分配给任何东西。并且更喜欢marks.length来硬编码数字5。您想要类似的东西，

double[] marks = new double[5];
for (int i = 0; i < marks.length; i++) {
    System.out.printf("Enter your marks for course %d : ", (i + 1));
    try {
        marks[i] = input.nextDouble();
    } catch (InputMismatchException e) {
        System.out.printf("%s is not a double.%n", input.nextLine());
        i--;
        continue;
    }
    total += marks[i];
}

Answer 2

您两次致电input.nextDouble()。将分配直接移到try-catch块中，然后删除第二个input.nextDouble()。像这样：

for (int i = 0; i < 5; i++){
   System.out.printf("Enter your marks for course %d : ", (i + 1));
   try { 
      marks[i] = input.nextDouble();
   } catch (InputMismatchException e) {
      System.out.println("this doesn't work");
      input.next();
      continue;
   }
   total += marks[i];
}

Answer 3

发生这种情况是因为您两次使用input.nextDouble()。在try中，使用类似value = input.nextDouble()的名称，然后在catch之后，marks[i] = value

即使没有异常抛出，程序也会要求2倍

3 个答案: