从文件流中读取一个单词的函数getword()的返回值为什么要这么设计？
Now for the function getword. We have written a more general getword than is necessary for this program, but it is not complicated. getword fetches the next ``word'' from the input, where a word is either a string of letters and digits beginning with a letter, or a single non?white space character. The function value is the first character of the word, or EOF for end of file, or the character itself if it is not alphabetic.
这是书上的代码：
// 返回值为什么要这么设计？
/* getword: get next word or character from input */
int getword(char *word, int lim)
{
int c, getch(void);
void ungetch(int);
char *w = word;
while (isspace(c = getch()))
;
if (c != EOF)
*w++ = c;
if (!isalpha(c))
{
*w = '\0';
return c;
}
for ( ; ??lim > 0; w++)
if (!isalnum(*w = getch()))
{
ungetch(*w);
break;
}
*w = '\0';
return word[0];
}
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#define MAXWORD 100
int getword(char *, int);
int binsearch(char *, struct key *, int);
/* count C keywords */
main()
{
int n;
char word[MAXWORD];
while (getword(word, MAXWORD) != EOF)
if (isalpha(word[0]))
if ((n = binsearch(word, keytab, NKEYS)) >= 0)
keytab[n].count++;
for (n = 0; n < NKEYS; n++)
if (keytab[n].count > 0)
printf("%4d %s\n",
keytab[n].count, keytab[n].word);
return 0;
}
