C does not have its own String data type like Java.
Only we can declare String datatype in C using character array or character pointer
For example :
char message[10];
or
char *message;
But you need to declare at least:
char message[14];
to copy "Hello, world!" into message variable.
- 13 : length of the "Hello, world!"
- 1 : for '\0' null character that identifies end of the string