ex3-1.c

嵌入式程序设计的十个实例的源代码。欢迎大家下载

#include <stdio.h>

#define	RANGE(type, name)				\
	{						\
	type minval, maxval, bit ;			\
	unsigned bits ;					\
	char *format ;					\
							\
	/* Measure size of data type */			\
	bits = 1 ; bit = (type) 1 ;			\
	while (bit <<= 1) bits++ ;			\
							\
	/* Signed or unsigned? (2's complement!) */	\
	if ((type) (1L << (bits - 1)) > 0)		\
		{					\
		format = "%12lu" ; /* unsigned */	\
		minval = (type) 0 ;			\
		}					\
	else						\
		{					\
		format = "%12ld" ; /* signed */		\
		minval = (type) 1 << (bits - 1) ;	\
		}					\
							\
	/* Assume two's complement */			\
	maxval = minval - 1 ;				\
							\
	printf("%20s (%2u bits): ", name, bits) ;	\
	printf(format, (long) minval) ;			\
	printf(" to ") ;				\
	printf(format, (long) maxval) ;			\
	printf("\n") ;					\
	}

int main()
	{
	printf("\nTesting range of UNSIGNED ints ...\n\n") ;
	RANGE(unsigned char,		"unsigned char"		) ;
	RANGE(unsigned short int,	"unsigned short int"	) ;
	RANGE(unsigned int,		"unsigned int"		) ;
	RANGE(unsigned long int,	"unsigned long int"	) ;

	printf("\nTesting range of SIGNED ints ...\n\n") ;
	RANGE(signed char,		"signed char"		) ;
	RANGE(signed short int,		"signed short int"	) ;
	RANGE(signed int,		"signed int"		) ;
	RANGE(signed long int,		"signed long int"	) ;

	return 0 ;
	}