How can I create a new matrix which stores the diagonals, but it first starts with a matrix full of zeros?

%A
rng('default')
r2 = randi(100,3,3); % Creating a 3x3 matrix, with random values from 1 to 100

%B
d = diag(r2) % Obtain the diagonal elements 

%C
Metod1 = d(2,1) % Using two parameters (row 2, column 1)
Metod2 = d(3) % Using one parametr (3rd element)

How can I create a new matrix (3x3) which stores the diagonals, but it first starts with a matrix full of zeros?

[Jonas]

so you want a zeros matrix with random diagonal elements?

diag(randi(100,3,1))

Answer 1

[Chunru]

% start with zero matrix
n=3;
a = zeros(3)

a = 3×3

0 0 0 0 0 0 0 0 0

% random entries along diagonal
a(1:n+1:n*n) = randi(100, [n 1])

a = 3×3

22 0 0 0 87 0 0 0 57

% alternatively
a = diag(randi(100,[n,1]))

a = 3×3

41 0 0 0 86 0 0 0 96

[Jonas Morgner]

Thank you :)