How to change the values of the corners in a matrix

Hi,

Lets say I have a 100 * 100 matrix filled with zeros and I need to change the 4 corners to the value 1. What would be the best way to alter it?

Answer 1

[Chunru]

a= zeros(10, 10);  % smaller matrix for easy display

% for corners
a([1 end], [1 end]) = 1;

a

a = 10×10

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