Don't understand what 's' is

%Origami fortune teller
clc; clear;
color = input('Enter (R)ed, (G)reen, (B)lue or (Y)ellow: ', 's');
if color == 'R' || color == 'G' || color == 'B' || color == 'Y'    %proceed    
    if color == 'R' || color == 'B'        
        num = input('Coose 1, 2, 5 or 6: ');        
        if num == 1            
            fprintf('Fortune 1 \n');        
        elseif num == 2            %fortune 2        
        elseif num ==5            %fortune 5        
        elseif num == 6            %fortune 6       
        else
            fprintf('Invalid inpuit! \n')        
        end
    else
        num = input('Choose 3, 4, 7 and 8: ');        
        if num == 3        
        elseif num == 4        
        elseif num == 7        
        elseif num == 8        
        else
            fprintf('Invalid Input! \n');        
        end
    end
else
    fprintf('Invalid input! \n');
end

This is an example code to demonstrate if/else statements and nested if/else statements, but I'm confused about what the 's' denotes in the color input. I'm attempting to complete a similar code, but it won't function with or without the 's' and I'm wondering if I'm doing something else incorrectly or if I'm misinterpreting this notation.

[Stephen23]

Note that if color is a scalar character you can simplify this

color == 'R' || color == 'G' || color == 'B' || color == 'Y'

using ismember:

ismember(color,'RGBY')

or using basic using logical operations:

any(color=='RGBY')

Answer 1

[Stephen23]

The input documentation describes the effect of its second optional input argument as "str = input(prompt,'s') returns the entered text, without evaluating the input as an expression."

Simply put:

• sans 's': executes the input text, e.g. if you input 'x' it will return the value of the variable x.
• with 's': returns the literal text, e.g. if you input 'x' it will return the character 'x'.

In general, evaluating arbitrary text provided by a user is not a good way to write code.