how to make if accept letters?

i know about 'if' code, but what i dont understand is why it tells me error?

error: 'y' undefined near line 33 column 16

error: called from

Code_6 at line 33 column 5

nam = input('Enter name: ', 's');
adrs = input('Enter address: ', 's');
num = input('Enter amount of purchase: $');
pur = input('Enter type of purchase (L for Laptop / D for Desktop): ', 's');
fprintf('\n')
switch pur
  case {'L' 'l'}
    disp('You have choosen Laptop as your type of puchase')
    if num <250
      disc = (0 / 100) * num;
      net = num - disc;
    elseif num <570
      disc = (5 / 100) * num;
      net = num - disc;
    elseif num <1000
      disc = (7.5 / 100) * num;
      net = num - disc;
    elseif num >1000
      disc = (10 / 100) * num;
      net = num - disc;
    endif
    fprintf('Name: %s\n', nam)
    fprintf('Address: %s\n', adrs) 
    fprintf('Net amount: $%.2f \n', net)
    #promt user to continue or not
    yesno = input('Do you wish to continue purchase? (y/n)', 's')
    fprintf('\n')
    if yesno = y;
      Code_6
    else
      disp('You have exit purchase screen, Goodbye.')
    endif

[per isakson]

Firstly, replace endif by end. And it's a good habit to have an else-clause in every if-end statement.

Answer 1

[Ameer Hamza]

Several problem:

1. = is an operator for assignment in MATLAB. For comparison, you need to use ==

if yesno == y

2. You want to compare the value to character 'y', just writing y means that you are referring to a variable

if yesno == 'y'

3. It is more of a suggestion, but it us better to use strcmp() for char arrays

if strcmp(yesno,'y')

[JJD]

thank you, this helps so much

[Ameer Hamza]

I am glad to be of help!