twordcount3.c

unix linux 编程实践源代码

/* twordcount3.c - threaded word counter for two files.	
 *		 - Version 3: one counter per file
 */

#include  <stdio.h>
#include  <pthread.h>
#include  <ctype.h>

struct arg_set {		/* two values in one arg */
		char *fname;	/* file to examine	 */
		int  count;	/* number of words	 */
};

main(int ac, char *av[])
{
	pthread_t      t1, t2;		/* two threads */
	struct arg_set args1, args2;	/* two argsets */
	void	       *count_words(void *);

	if ( ac != 3 ){
		printf("usage: %s file1 file2\n", av[0]);
		exit(1);
	}
	args1.fname = av[1];
	args1.count = 0;
	pthread_create(&t1, NULL, count_words, (void *) &args1);

	args2.fname = av[2];
	args2.count = 0;
	pthread_create(&t2, NULL, count_words, (void *) &args2);

	pthread_join(t1, NULL);
	pthread_join(t2, NULL);
	printf("%5d: %s\n", args1.count, av[1]);
	printf("%5d: %s\n", args2.count, av[2]);
	printf("%5d: total words\n", args1.count+args2.count);
}
void *count_words(void *a)
{
	struct arg_set *args = a;	/* cast arg back to correct type */
	FILE *fp;
	int  c, prevc = '\0';
	
	if ( (fp = fopen(args->fname, "r")) != NULL ){
		while( ( c = getc(fp)) != EOF ){
			if ( !isalnum(c) && isalnum(prevc) )
				args->count++;
			prevc = c;
		}
		fclose(fp);
	} else 
		perror(args->fname);
	return NULL;
}