strtok.c

#include <stdio.h>
#include <stdlib.h>

//strtok的实现和strtok_r一样，只是用一个static char*来维护saveptr

char *strtok_r(char *str,const char *delim,char **saveptr)
{
	char *ret;
	if(str==NULL)
		str=*saveptr;
	while(*str && strchr(delim,*str))
		str++;
	if(*str=='\0')
		return NULL;
	ret=str;
	while(*str && !strchr(delim,*str))
		++str;
	if(*str)
		*str++='\0';
	*saveptr=str;
	return ret;
}

int main(int argc, char *argv[])
{
	char *str1, *str2, *token, *subtoken;
	char *saveptr1=NULL, *saveptr2=NULL;
	int j;

	if (argc != 4) {
		fprintf(stderr, "Usage: %s string delim subdelim\n",
			argv[0]);
		exit(EXIT_FAILURE);
	}

	for (j = 1, str1 = argv[1]; ; j++, str1 = NULL) {
		token = strtok_r(str1, argv[2], &saveptr1);
		if (token == NULL)
			break;
		printf("%d: %s\n", j, token);

		for (str2 = token; ; str2 = NULL) {
			subtoken = strtok_r(str2, argv[3], &saveptr2);
			if (subtoken == NULL)
				break;
			printf(" --> %s\n", subtoken);
		}
	}

	exit(EXIT_SUCCESS);
}