Very simple multi array c program - problem noob

Question

I can't figure out where the problem is in my program?

#include <stdio.h>
int main()
{
  int a[2][2]={{1,2},{3,4}};
  printf("The value of a[2][1] is %d",a[2][1]);
  return(0);
}

I expected the answer to be 3, it's actually wow! 32765 wait! what!? I'm pretty confused. Can someone help?

So the valid indexes are from `a[0][0]` to `a[1][1]`. `a[2][1]` is outside the array. — Barmar, Jan 26 '21 at 02:09
Please take some time with a couple of beginners books, or take a class or two. — Some programmer dude, Jan 26 '21 at 02:09
After thinking about how that works it's an extremely awful way to assign things, and a great way to get confused. So one has an 2x2 array two rows and two columns, and any mathematician would say row 1 column 1 we have some value. I know, I'll have to get used to it but row 0 column 0 doesn't jive. For one thing you define an array n x n so it's sooo much easier to envision row n column n than to always have to think about the position in the array you actually want is n-1 n-1. — ChristopherDude22, Jan 26 '21 at 02:20

score 1 · Answer 1 · answered Jan 26 '21 at 02:10

1

You don't have anything in the spot a[2][1]. I think what you meant to put is a[1][0]. Remember that the index starts at 0 not at 1.

The reason why you are getting that big number is because that number was already sitting there in that memory location. It has nothing to do with the array you created.

answered Jan 26 '21 at 02:10

Mr.Young

324
5
14

Thanks. That's a crazy way to always have to think of the arrays as n-1 x n-1. – ChristopherDude22 Jan 26 '21 at 02:26
@ChristopherDude22 You'll get used to it. It's a pretty standard thing in programming. – Mr.Young Jan 26 '21 at 02:28

Very simple multi array c program - problem noob

1 Answers1