Questions

ptr pointer is constant. In ptr = yourbuf the program is trying to modify it, hence an error.

If you read newspaper daily, then you may be aware of the four coloured dots on the corner of the newspaper. 

The four dots CMYK — blue (Cyan), pink (Magenta), Yellow and black (Kalio) are registration marks used during printing to help ensure the print is aligned properly. Any colour can be obtained by adding the correct proportion of these four colours.

CMYK is used as a base for the colours used in printing newspapers, and these four colours are often printed on the paper in either a heart, dot, or square shape.

To print an image, the plates of all these colours are laid out on a page separately and lined up in the same spot while printing. If those four dots are blur or you find the colours overlapping on the image it means the printing is not good. To print an accurate and perfect image, the colors and shape must be arranged precisely and must be claear sharp in order to get the best output.

That's why CMYK is also called registration mark. As physically checking all the pages of the paper is not possible for a printer who prints number of news papers daily, he just checks these dots.

Copper Iodide is the systematic name of the given compound (CuI)s.

Full binary tree loses its nature when operations of insertions and deletions are done. For incomplete binary trees, extra storage is required and overhead of NULL node checking takes place. So complete binary tree is the better one since the property of complete binary tree is maintained even after operations like additions and deletions are done on it.

You have to actually count all the balls in the pyramid.
Simple way is to count the balls in each level.

So lower most level lets say 1st level has 4 x 4 balls; i.e. 16 balls
Similarly 2nd level has 3 x 3 balls; i.e. 9 balls.
3rd level has 2 x 2 balls; i.e. 4 balls.
The top most level has just 1 ball.

So the total number of balls is 16+9+4+1 = 30.

So the image has 30 Balls in all.

Vitamin K helps in clotting of blood. It is used by the body to help blood clot.

Warfarin (Coumadin) is used to slow blood clotting. By helping the blood clot, vitamin K might decrease the effectiveness of warfarin (Coumadin).