S = { 'A','B','C' } % create horizontal cell array
'A' 'B' 'C'
strjoin(S,'') % concatenate strings using strjoin() (recommended, available with version: R2016b)
ABC
strcat(S{:}) % concatenate strings using strcat()
ABC
cell2mat(S) % concatenate strings using cell2mat()
ABC
['A','B','C'] % simple array
ABC
S = { 'A','B','C' }
strjoin(S,',')
A,B,C
strjoin(S) % default: space between strings
A B C
using strcat() (not recommended for Matlab versions > R2016b)
strcat( cell2mat(strcat(S(1:end-1)',{','})'), S{end} )
A,B,C
steps explained
1) add comma to each string
strcat(S',{','})
'A,'
'B,'
'C,'
2) concatenate strings (cell2mat is used to covert string from cell-array into plain char)
cell2mat(strcat(S',{','})')
A,B,C,
3) for only adding the comma between strings, we need add the last string without comma
strcat( cell2mat(strcat(S(1:end-1)',{','})'), S{end} )
A,B,C