Error entering variables as strings

I am having some issues trying to get this code to function properly. It is supposed to help me formulate categorical logic statements quickly. I am assigning the varibles to the strings properly? All varibles should have the string as:

varible = input('Prompt: ', 's')

But I am still getting this error:

"Matrix dimensions must agree"

Here is my code.

%Categorical Syllogisms%
%Enter the categorical syllogism's part in standard form.%
disp('Enter the categorical syllogism parts in standard form.')
disp('Use all lowercase when entering your terms.')
quant = input('Quantifier: ','s');
if isempty(quant)
    disp('Error, no quantifier entered.')
end
subject_term = input('Subject Term: ','s');
if isempty(subject_term)
    disp('Error, no subject term entered.')
end
copula = input('Copula: ','s');
if isempty(copula)
    disp('Error, no copula entered.')
end
predicate = input('Predicate Term: ','s');
if isempty(predicate)
    disp('Error, no predicate entered')
end

%Categorical Proposition Type%
if quant ==  'all' 
    if copula == 'are' 
        disp('Type A statement.')
        disp('Quantity/Quality: Universal/Affirmative')
        statement = 'A';
    else
        disp('Invalid copula entered.')
    end
if quant == 'no'
    if copula == 'are' 
        disp('Type E statement.')
        disp('Quantity/Quality: Universal/Negative')
        statement = 'E';
    else
        disp('Invalid copula entered.')
    end
if quant == 'some'
    if copula == 'are' 
        disp('Type I statement.')
        disp('Quantity/Quality: Particular/Affirmative')
        statement = 'I';
    if copula == 'are not' 
        disp('Type O statement.')
        disp('Quantity/Quality: Particular/Negative')
        statement = 'O'; 
    else 
        disp('Invalid copula entered.')
    end
    end
else
    disp('Invalid quantifier entered.')
end
end
end

Answer 1

[Steven Lord]

try
    'no' == 'all'
catch ME
    disp(ME.message)
end

Matrix dimensions must agree.

'no' is a char row vector with two elements. 'all' is a char row vector with three elements. You can't compare a row vector with two elements and a row vector with three elements using ==. Use strcmp or matches instead.

if strcmp('no', 'all')
    disp('Match')
else
    disp('No match')
end

No match

if strcmp('all', 'all')
    disp('Match')
else
    disp('No match')
end

Match

doesMatch1 = matches('no', 'all')

doesMatch1 = logical
   0

doesMatch2 = matches('all', 'all')

doesMatch2 = logical
   1

Or since you have a small finite list of allowed values, you could use switch and case.

[Jonah Schmidt]

Thank you!