In addition to my previous post on the 1dimensional array 1

[iamjd]

The following code should take the isbnSum variable and divide is by 11 and if the answer is evenly divided then it should return 1 to the isValid boolean.

I am not sure on what technique or approach I should take in order to do so. Can someone possibly point me in the right direction?

#include <stdafx.h>

int isbn[10];

int main()
{
	bool isValid;
	int isbnSum=0;
	int i;

	for (i=0;i<10;i++)
	{
		printf("Enter digit # %d of isbn number.\n", i + 1);
		scanf("%d", &isbn[i]);
	}

	for (i=0;i<10;i++)
	{	
		isbnSum += isbn[i];
	}

	isValid = (isbnSum / 11);

	if(isValid)
	printf("isbn is valid.\n");
	else
	printf("isbn is invalid\n");

	return 0;
}

 

[xwb]

Try this

isValid = (isbnSum % 11) == 0;

This is one way of checking whether isbnSum is divisible by 0. The modulo operator % can be thought of as the remainder. It is not a proper modulo function: not mathematically anyway but for what you're doing, it should be OK.

 

[lionelhill]

xwb, sorry to be really stupid about this, but I'm definitely a bit mathematically challenged: what's the difference between the remainder of an integer division as given by % and a proper mathematical modulus? I always assumed they were the same.
Thanks in advance...

 

[mingis]

iamjd, as I remember, the last digit of ISBN is a control one and is a 11-basis digit, accepting values 0..9 and 'X', concerning to be value 10. Therefore simply scanf() will not work, you should input it as string or character and then evaluate.