STRNCMP STRNCMP String Compare Function To Length N 

Usage

Compares two strings for equality, but only looks at the
first N characters from each string.  The general syntax 
for its use is

  p = strncmp(x,y,n)

where x and y are two strings.  Returns true if x
and y are each at least n characters long, and if the
first n characters from each string are the same.  Otherwise,
it returns false.
In the second form, strncmp can be applied to a cell array of
strings.  The syntax for this form is

  p = strncmp(cellstra,cellstrb,n)

where cellstra and cellstrb are cell arrays of a strings
to compare.  Also, you can also supply a character matrix as
an argument to strcmp, in which case it will be converted
via cellstr (so that trailing spaces are removed), before being
compared.