## switchcase

### Instructions

Write a program that takes a string and reverses the case of all its letters.

- Other characters remain unchanged.

- You must display the result followed by a '\n'.

- If the number of arguments is not 1, the program displays '\n'.

### Expected output

```console
student@ubuntu:~/piscine/test$ go build
student@ubuntu:~/piscine/test$ ./test "SometHingS iS WronG"
sOMEThINGs Is wRONg
student@ubuntu:~/piscine/test$ ./test

student@ubuntu:~/piscine/test$
```