Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

In the following code, out = cryptoshift(in, shift) : while using a sting in the in argument and shift this by an integer value, it shows the error "Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses." How to solve this?

function out = cryptoshift('ABC',5 )
numbers = double(lower(in))-96;
codednumbers = zeros(1,length(numbers));
for i = 1:length(numbers);
    if numbers(i) >= 1 & numbers(i) <= 26
        codednumbers(i) = mod(numbers(i)+shift-1,26)+1;
    else
        codednumbers(i) = numbers(i);
    end
end

out = char(codednumbers+96);

Answer 1

[Ameer Hamza]

In MATLAB, the input argument in the function definition must be variables. You are writing constant values. Change the function definition to the following

function out = cryptoshift(in, shift) % <--- use variable names here
numbers = double(lower(in))-96;
codednumbers = zeros(1,length(numbers));
for i = 1:length(numbers)
    if numbers(i) >= 1 & numbers(i) <= 26
        codednumbers(i) = mod(numbers(i)+shift-1,26)+1;
    else
        codednumbers(i) = numbers(i);
    end
end
out = char(codednumbers+96);
end

and then call it like this

cryptoshift('ABC', 5)