i changed my codes. its still not working
A number of things are wrong
1 - you cannot compare C strings using == you need to use strcmp()
2 - the cpos array is an array of chars, not a C string because you have not added a terminating '\0'
3 - your RFID codes have a very odd trailing character. Copy your code from here back to the IDE to see them. In the IDE they are 13 characters long
4 - the use of the goto command is deprecated and is not necessary. The loop() function does what its name implies, ie it loops, so use that to read the ID characters from Serial