Generate Matrix

Question

I am new to MATLAB and I want to write a simple program to generate an n x n matrix A such that:
1. a₁₁ = 2
2. a₂₂ = ... = a_nn = 5
3. 0 everywhere else

Can the program take n as an argument? So that I will have to choose an n every time I run the program.

Thanks!

Answer 1

n = 8;             %# input value, matrix size

A = 5.*eye(n);     %# put 5 on diagonal, zeros elsewhere
A(1,1) = 2;        %# first element

Answer 2

Here's another way of doing the same.

n=8;
A=diag([2 5*ones(1,n-1)]);