Error using fscanf ???

Hi to all. Please help. I'm new in Matlab, so i don't really understnad why i get this error.

"Error using fscanf
Invalid file identifier. Use fopen to generate a valid file identifier. Error in gaspp (line 22)
num = fscanf(fid, '%d', [1,1]);  % Number of nodes"

i found a code related to my project so i tried it and it was running. but when i finish input then it shows an error.

this is my code

disp('==============================');

disp('Masukkan Parameter Program'); 

disp('==============================');

f_input = input('>> Nama Input File : ','s'); % Contains network info 

startNode = input('>> Node sumber : ');    % Source node 

endNode = input('>> Node tujuan : ');  % Destination node

nind = input('>> Ukuran populasi : ');  % Population size

Pc = input('>> Probabilitas crossover : '); % Crossover probability 

Pm = input('>> Probabilitas mutasi : ');    % Mutation probability 

ngener = input('>> Batas generasi : ');  % Generations limit

% -------------------------------------------------------------

% NETWORK BUILDING

% -------------------------------------------------------------

fid = fopen(f_input,'r');

*num = fscanf(fid, '%d', [1,1]);% Number of nodes* 

edges = fscanf(fid, '%d', [1,1]);% Number of edges 

source_node = zeros(1,edges);% Set of source nodes 

dest_node = zeros(1,edges);% Set of end nodes 

link_cost = zeros(1,edges);% Set of link cost 

unlink_cost = 1000;% Set of unlink cost

thanks before

Answer 1

[Walter Roberson]

When you are prompted for Nama Input, you need to type in the name of an existing file.

[Khoirunnisya Zawawi]

thank you for your answer, Walter. so i should make a new file for that? a blank file or what? cause when i get the code it's only contains some of .m file related to genetic algorithm (my project is about GA). thanks before

[Walter Roberson]

The file should contain two integers separated by whitespace (in text form). The first of them should be the number of nodes, and the second of them should be the number of edges.

Possibly code you did not show reads more information from the file.

[Khoirunnisya Zawawi]

like this 10 14; ? or [10 14];

[Walter Roberson]

Just numbers and spaces no brackets.

[Khoirunnisya Zawawi]

found it. thank you so much :)

[Khoirunnisya Zawawi]

Hi Walter. i found another error in this code, its about horzcat. can you help me about it? this is my new question https://www.mathworks.com/matlabcentral/answers/308260-how-to-solve-this-error-error-using-horzcat-dimensions-of-matrices-being-concatenated-are-not-cons

i really appreciate it if you could help, thank you so much :)

[Bagus Adhi]

I'm sorry maybe its to late for asking about this question now. I want to ask is "is there any code that should be changed to clear the error", cause i cannot find the answer by reading all the aswer between Ms. Khoirunnisya and Mr. Walter. I really need your help, this answer will help me for my Presentation. Thank You