Create a Matrix with a specific main diagonal

I want to create a matrix of all one's with the main diagonal of value n.

Answer 1

[Thorsten]

 val = 50; N = 10; 
 X = diag(repmat(val-1, 1, 10)) + ones(N)

Answer 2

[dpb]

Multiple ways possible; one--

>> N=5;   % diagonal value
>> sz=3;  % size
>> m=ones(sz)+diag(repmat(N-1,1,sz))
m =
   5     1     1
   1     5     1
   1     1     5
>> 

doc diag % for details on optional arguments for different resulting types

Answer 3

[Stephen23]

One very simple solution:

>> X = +~eye(4);
>> X(X==0) = 5
X =
     5     1     1     1
     1     5     1     1
     1     1     5     1
     1     1     1     5

Answer 4

[Andrei Bobrov]

d = randi(35,5,1);
out = ~eye(5) + diag(d);