C语言避免重复包含实例

// names.h --revised with include protection

#ifndef NAMES_H_
#define NAMES_H_

// constants
#define SLEN 32

// structure declarations
struct names_st
{
    char first[SLEN];
    char last[SLEN];
};

// typedefs
typedef struct names_st names;

// function prototypes
void get_names(names *);
void show_names(const names *);
char * s_gets(char * st, int n);

#endif