Question

I am trying to do some C problems I found and this one has me stuck. I have a 10×10 two dimensional array with every element equaling zero. So it looks like this:

0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0

I need to set the top triangle to be 1s. So it would look like this:

1 1 1 1 1 1 1 1 1 1
0 1 1 1 1 1 1 1 1 0
0 0 1 1 1 1 1 1 0 0
0 0 0 1 1 1 1 0 0 0
0 0 0 0 1 1 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0

How would I do this besides manually doing arr[0][0] = 1; arr[0][1] = 1; arr[0][2] = 1 and so on?

Answer 1

This will do want you need:

n = 10;
for(i = 0; i < n/2; i++)
{
   for(j = i; j < n - i; j++)
      arr[i][j] = 1;
}