Having difficulty with java while loop exit

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Hi,

I have a problem where the user inputs integers until they type "done", at which point the even and odd averages are calculated and displayed. I've nearly got it, but can't figure out how to get around the scanner expecting an int input, but gets a string, so it crashes there (mismatched type exception).

Java

static void problem4()
	    {
	    	int evenCount = 0;
	    	int oddCount = 0;
	    	int evenTotal = 0;
	    	int oddTotal = 0;
	    	double evenAverage;
	    	double oddAverage;
	    	String endKey = "DONE";
	    	int entry;
	    	
	    	while (true)
	    	{
	    		System.out.print("Enter a number or 'done' to quit: ");
	    		
	    		entry = input.nextInt();
	    		
	    		if (input.nextLine().toUpperCase().equals(endKey))
	    		{	
	    			break;
	    		}
	    		    		
	    		if (entry % 2 == 0)
	    		{
	    			evenCount++;
	    			evenTotal = evenTotal + entry;
	    		}
	    		else
	    		{	
	    			oddCount++;
	    			oddTotal = oddTotal + entry;
	    		}
	    	}		
	    		
	    	evenAverage = (double) evenTotal / (double) evenCount;
	    	oddAverage = (double) oddTotal / (double) oddCount;
	    	System.out.println("Even average: " + evenAverage);
	    	System.out.println("Odd average: " + oddAverage);
	    	
	    }

What I have tried:

I've tried instead of doing nextInt(), just doing next(), but that didn't work. Still quite new to Java.

Posted 1-Feb-22 1:01am

Grelm

Updated 1-Feb-22 10:52am

Sean Ewington

v2

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M Imran Ansari · Accepted Answer · 2022-02-01T01:32:00

Take input as string because you are checking with "Done" which is string and when you take string as input through input.nextInt() it will throw an exception. I had modified you code little bit:

static void problem4()
{
	int evenCount = 0;
	int oddCount = 0;
	int evenTotal = 0;
	int oddTotal = 0;
	double evenAverage;
	double oddAverage;
	String endKey = "DONE";
	String entryVal;
	int entry;
		
	while (true)
	{
		System.out.print("Enter a number or 'done' to quit: ");
		entryVal = entryVal.nextLine();
		if (entryVal.nextLine().toUpperCase().equals(endKey))
		{	
			break;
		}
				
		entry = Integer.parseInt(entryVal);		
		if (entry % 2 == 0)
		{
			evenCount++;
			evenTotal = evenTotal + entry;
		}
		else
		{	
			oddCount++;
			oddTotal = oddTotal + entry;
		}
	}		
		
	evenAverage = (double) evenTotal / (double) evenCount;
	oddAverage = (double) oddTotal / (double) oddCount;
	System.out.println("Even average: " + evenAverage);
	System.out.println("Odd average: " + oddAverage);
	
}

CPallini · Accepted Answer · 2022-02-01T01:37:00

You should get a string as input and then try to parse it as a number.

Java

System.out.print("Enter a number or 'done' to quit: ");

entry = input.nextLine();

if (entry.toUpperCase().equals(endKey))
{
  break;
}

int n;
try
{
  n = Integer.parseInt(entry);
  if (n% 2 == 0)
  {
    evenCount++;
    evenTotal = evenTotal + n;
  }
  else
  {
    oddCount++;
    oddTotal = oddTotal + n;
  }
}
catch (NumberFormatException e)
{
  System.out.println("invalid entry");
}

Having difficulty with java while loop exit

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