Need Help With Error Input Dealing

[tongjia19]

Hi all. This is a part of my program, and I have been experiencing some problems.

The program works as intended, but then I thought I should add in some error checking into it. When I prompt the user to input numbers, I would like the program to ask the user to input the number again if he/she entered a non-number. However, the way I've written the code right now just seems to print the error message infinate times.

Can someone give some advice? Thanks.

int readlist(int arr[], int siz)
{
	int i;
	int status;
	int ch;

	printf("\nEnter %i numbers: \n", siz);

	for(i = 1; i < siz + 1; i++)
	{
		printf("%i) ", i);

		status = scanf("%i", arr++);
	
		while(status != 1)
		{
			printf("What? Naw... Again pls.. \n");
			status = scanf("%i", arr);
		}
	}

	return *arr;
}

[Salem]

The problem is, you increment arr before you know whether you were successful or not.

[tongjia19]

The problem is, you increment arr before you know whether you were successful or not.

So.. like this?

for(i = 1; i < siz + 1; i++)
	{
		printf("%i) ", i);

		status = scanf("%i", arr);
	
		while(status != 1)
		{
			printf("What? Naw... Again pls.. \n");
			status = scanf("%i", arr);
		}
		arr++;
	}

But it's still printing infinate "What? Naw... Again pls.."s..

[Salem]

Well if you type "hello" and scanf is waiting for an integer, then it will loop forever.

If scanf fails, you should remove some erroneous input, typically up to the next newline.

Ways of "flushing" the input NOT involving fflush(stdin) are in the FAQ.

[tongjia19]

Well if you type "hello" and scanf is waiting for an integer, then it will loop forever.

If scanf fails, you should remove some erroneous input, typically up to the next newline.

Ways of "flushing" the input NOT involving fflush(stdin) are in the FAQ.

Thanks a lot. Found the line

while ((ch = getchar()) != '\n' && ch != EOF);

and it fixed the problem.

[CommonTater]

You might like to play around with this...
The trick is to check the loop AFTER the entry...

     status = 0;
     do 
        { printf("Enter a number : ");
           status = scanf("%i", &arr);  
           If (status != 1)
             Printf("\nError... ");  }
    while(status != 1)

A couple of hints...
Always tell your operator what is expected... they're not mind readers.
Always inform them of errors but in the most innocuous way possible.