byte is not valid data type in c code example

Example: c data types

Type	             Size (bytes)	                     Format Specifier
int	                at least 2, usually 4	                 %d, %i
char	             1	                                     %c
float	             4	                                     %f
double	             8	                                     %lf
short int	         2 usually	                             %hd
unsigned int        at least 2, usually 4	                 %u
long int	        at least 4, usually 8	                 %ld, %li
long long int	        at least 8	                         %lld, %lli
unsigned long int	    at least 4	                         %lu
unsigned long long int	at least 8	                         %llu
signed char           	1	                                 %c
unsigned char	        1	                                 %c
long double	      at least 10, usually 12 or 16	             %Lf