The Select Clause can occur 65535 times in a cobol program. Theoritically the answer to your question is that you can have 65535 files in a cobol program.
There might be other limits as the JCL limits which I am not sure about.
hi can you please clarify us how do you say we can have 65535 select clause in a program. for a particular pgm executed through an EXEC statement, we can have 3273 DD statements. this means we can have only 3273 files.