tmp2.c

linux下的Ｃ语言开发

/*-*/
/********************************************************
 * Question:						*
 *	We fixed the problem in the last question, but	*
 *	now we have another.  What does the following	*
 *	program print and why?				*
 ********************************************************/

/*+*/
#include <stdio.h>
#include <string.h>

/********************************************************
 * tmp_name -- return a temporary file name		*
 *							*
 * Each time this function is called, a new name will	*
 * be returned.						*
 *							*
 * Warning: There should be a warning here, but if we	*
 *	put it in we would answer the question.		*
 *							*
 * Returns						*
 * 	Pointer to the new file name.			*
 ********************************************************/
char *tmp_name(void)
{
    static char name[30];	/* The name we are generating */
    static int sequence = 0;	/* Sequence number for last digit */

    ++sequence;	/* Move to the next file name */

    strcpy(name, "tmp");

    /* But in the squence digit */
    name[3] = sequence + '0';

    /* End the string */
    name[4] = '\0';

    return(name);
}

int main()
{
    char *tmp_name(void);	/* get name of temporary file */
    char *name1;		/* name of a temporary file */
    char *name2;		/* name of a temporary file */

    name1 = tmp_name();
    name2 = tmp_name();

    printf("Name1: %s\n", name1);
    printf("Name2: %s\n", name2);
    return(0);
}