当什么都没输入时，为什么我的循环转到else条件？

Question

Good evening,

I'm at a loss as to why this loop isn't working at all. It's ruining my entire application. below is the code:

    System.out.println("Please tell me what to count till?");
    do  
    {
        try
        {
            newEndingValue= input.nextInt();
            if(newEndingValue >= 0 || newEndingValue <= 0) 
            {
               break; //breaks the loop
            }
        }
        catch (InputMismatchException e) 
        {
            System.out.println("My Apologies, but COMMAND NOT RECOGNIZED!" + "\nPlease tell me what to count till?");
            input.next();       

        }           
    }   
    while(!input.hasNextInt()); 

    v.setEndingValue(newEndingValue);


System.out.println("Please tell me what to count from?");
if(increasingOrDecreasing.equalsIgnoreCase("Increasing")|| increasingOrDecreasing.equals("++") || increasingOrDecreasing.equals("+"))
    {
    do  
    {
      try 
      {
            newInitialValue = input.nextInt();
            if(newInitialValue < v.getEndingValue()) 
                {
                 break; 
                }
            else{ 
                System.out.println("My Apologies, but starting point value must be smaller than ending point value!" + "\nPlease tell me what to count from?"); 
                newInitialValue = (v.getEndingValue()+10);//overrides the value to something that forces the loop back
                }
        }
        catch (InputMismatchException e) 
            {
            System.out.println("My Apologies, but COMMAND NOT RECOGNIZED!" + "\nPlease tell me what to count from?"); 
            input.next();       
            }           
     }  
    while(!input.hasNextInt() || newInitialValue > v.getEndingValue());
     }
else
{
    do 
    {
    try 
        {
        newInitialValue = input.nextInt();
        if(newInitialValue > v.getEndingValue()) 
            {
             break; //breaks the loop
            }
        else{ 
            System.out.println("My Apologies, but starting point value must be larger than ending point value!" + "\nPlease tell me what to count from?"); 
            newInitialValue = (v.getEndingValue()-10);//overrides the value something that forces the loop back
            }
        }
    catch (InputMismatchException e)
        {
        System.out.println("My Apologies, but COMMAND NOT RECOGNIZED!" + "\nPlease tell me what to count from?"); 
        input.next(); //consumes the erroneously typed string value 
        newInitialValue = (v.getEndingValue()-10);
        }           
    }   
    while(!input.hasNextInt() || newInitialValue < v.getEndingValue());
    }

So the output is when entered a no, and then 1000 as follows:

Please tell me what to count till?

no

My Apologies, but COMMAND NOT RECOGNIZED!

Please tell me what to count till?

1000

Please tell me what to count from?

My Apologies, but starting point value must be smaller than ending point value!

Please tell me what to count from?

Why is it going straight to the second written else statement? Why is it skipping user entry for newInitialValue? Please note that if edit code after ending value block to below after entering a string for newEndingValue and then correctly enter a number, this rids me of my error but generates another one if ran again and the user cooperates:

...
newInitialValue = input.nextInt(); //essentially gets skipped over by compiler only when previous catch statement is triggered
System.out.println("Please tell me what to count from?");
if(increasingOrDecreasing.equalsIgnoreCase("Increasing")|| increasingOrDecreasing.equals("++") || increasingOrDecreasing.equals("+"))
{...

additionally since its printing out "but starting point value must be smaller than ending point value" we can deduce its working with if(incre...) loop and the do and try loops respectively. But its skipping the (newI... = input...) and the if(newIntia...) lines of code. i know this cause even manually entering in newInitialValue = 2 (within paramenter) it still goes to this else clause.

Answer 1

-_- So the issue is within the while statements:

while(!input.hasNextint())

this looks ahead and checks the next user input, but since the catch consumed one it looks to the next next and it gets murky... essentially if i don't use this it works. instead i used:

while(isError == true)

and under the do loop with the nested if statement i have:

if(blah blah blah){
isError=false;
break;

and before the next loop block i simply override the isError

isError=true;
//next block of code

Answer 2

这里的问题是，您说要让java在value 1为true或value2为true或value3为true的情况下执行某些操作，然后再在else上说要使用or进行相同操作。您已经了解到需要使用and &&为了帮助Java理解else参数。