Modify MATLAB function below, named isref, that accepts a matrix as input and returns 1 if the matrix has row echelon form and 0 if it does not.

function classification = isref(A)

% Returns 1 if the matrix A is row echelon; 0 otherwise.

[m n] = size(A); % set the number of rows (m) and columns (n) of A

lastleading = -1; % assures row 1 satisfiews the row echelon condition

classification = 1; % assume A is row echelon until proven otherwise

for r=1:m

% Replace these comments with appropriate MATLAB code that

% checks the leading entry of each row and

% sets classification = 0 if the matrix

% fails to be row echelon.

end

end