Thread: Incorrect Difference

I'm trying to make a simple calculator program....but when I start to subtract numbers..it gives my incorrect answer....

Code:

#include <stdio.h>
int main()
{
	int a[2],i, diff=0;
	
	printf("\n\tSubtract Numbers\n\n");
	for(i=0; i<2; i++)
	{
		printf("Enter a number: ");
		scanf("%d", &a[i]);
		diff-=a[i];
	}
	printf("\n\tThe difference is %d\n", diff);
}

Output:

Enter a number: 13
Enter a number: 15
The difference is -28

It should be -2 right??...because 13-15=-2