The meaning of code on this program

Hi.

i met a question on this program, this is professor's code.

While, i confused for the M(r,c) = input(': ');

What is purpose of this code and why it is used on this program ?

% question: let users enter 9 numbers and output a 3*3 matrix,

clear all
clc

rows = 3;
cols = 3;
M = [];
for r = 1:rows
    for c = 1:cols
        fprintf('Enter the value for row %d column %d',r,c);
        M(r,c) = input(': ');
        
    end
end

Answer 1

[KSSV]

You shoould run the code o understand it your self.

What is purpose of this code and why it is used on this program ?

The purpose of the line is to take the user input, for rth row and cth column. Read about the function input. Try

doc input
help input

There should be a small change in the code. Dont use

M = [] ; 

You should initilaize the matrix M.

M = zeros(rows,cols) ; 

[Shuoze Xu]

Ok, thank you.

[Shuoze Xu]

While i know the meaning of input.

I just cannot understand why it used on here?

I know the meaning of fprintf() and input(), but why this code use fprintf() to show the comment for users

fprintf('Enter the value for row %d column %d',r,c);

M(r,c) = input(': ');

[KSSV]

fprintf is used to print the information.

[Shuoze Xu]

Yes, i known it.

My question is i always use the fprintf() to print infomation like that frprintf('The result is %d\n',vairable name)

But what is meaing of M(r,c) on this programming?

It means matrix?

[KSSV]

Yes M is matrix and M(r,c) stands for element at rth row and cth column.

[Shuoze Xu]

Sorry maybe MY description is not very clear, my main confusion is that the problem I encountered before is to write "add number" in input, I have never seen this kind of usage before.

i always use x = input("Enter the number: ")

fprint("The number is %d\n",x);

[Shuoze Xu]

Anyway, thank you for your patience, thank you very much.