i want to make a function ''user(A,B,C)'' in which A is an image , B is [X,Y] / [R] where R, X,Y are numerical values and C is a string ? please help me out !

I want to implement if condition on B and C to obtain outputs but getting an error of "Undefined function for input arguments of type uint8 " ?? for e.g

         if B == [X,Y] && C== 'TL'
         calculations
         end

         if B == [R]  && C == 'RO'
         calculations
         end

[Guillaume]

The portion of code that you've shown is unlikely to result in an 'Undefined function' error message. Post the bit of code that causes the error and the entirety of the error message (it should tell you which function is undefined).

Typical cause for this error is that the function you're calling is not on the matlab path.

Finally use strcmp for string comparison rather than == (which would result in an error if the two strings have different length).