Question

我想强制用户选择1，然后才能继续选择2，任何帮助都会受到赞赏。（注意我到目前为止只执行过if，while，for，do .... while，java中的方法和数组）

Scanner sc = new Scanner(System.in);   

int[] ages = new int[3];
int choice;
do {
   System.out.println("Average Age program");
   System.out.println("Enter 1 to enter ages");
   System.out.println("Enter 2 to calculate the average Age");
   System.out.println("Enter 0 to Exit");
   choice = sc.nextInt();
   switch(choice) {
       case 1:
           acceptAges(ages);
           break;

       case 2:
           averageAge(ages);
           break;

       default:
           System.out.print("invalid option");

    } 

  } while(choice != 0);
}

Answer 1

在2被选中至少一次之前，您无法显示选择1。

 Scanner sc = new Scanner(System.in);   

 int[] ages = new int[3];
 int choice;
 boolean is2Enabled=false,
 do{
   System.out.println("Average Age program");
   System.out.println("Enter 1 to enter ages");
   if(is2Enabled)
     System.out.println("Enter 2 to calculate the average Age");
   System.out.println("Enter 0 to Exit");
   choice=sc.nextInt();
   switch(choice)       
   {
       case 1:
       acceptAges(ages);
       is2Enabled=true;
       break;

       case 2:
       if(is2Enabled)
         averageAge(ages);
       else
         System.out.print("invalid option");
       break;

       default:
       System.out.print("invalid option");
    } 
  }while(choice != 0);
}

强制用户在选项2之前选择选项1

1 个答案: