exc/k&r/04-funcs-and-prog-struct/04-find/find-book.c

#include <stdio.h>

#define MAXLINE 1000 /* maximum input line length */

int getln(char line[], int lim);
int strindex(char source[], char searchfor[]);

/* find: prints lines containing pattern, returns number of matching lines */
int find(char *pattern, char lineno_flag, char except_flag)
{
    char line[MAXLINE];
    int found = 0;
    long lineno;

    for (lineno = 1; getln(line, MAXLINE) > 0; lineno++)
        if ((strindex(line, pattern) >= 0) != except_flag) {
            if (lineno_flag)
                printf("%ld:", lineno);
            printf("%s", line);
            found++;
        }
    return found;
}

/* getline: get line (including \n) into s, return length */
int getln(char *s, int lim)
{
    int c, i = 0;
   
    while (--lim > 0 && (c = getchar()) != EOF && (s[i++] = c) != '\n')
        ;
    s[i] = '\0';
    return i;
}

/* strindex: return index of t in s, -1 if none */
int strindex(char s[], char t[])
{
    int i, j, k;
    for (i = 0; s[i]; i++) {
        for (j=i, k=0; t[k] && s[j] == t[k]; j++, k++)
            ;
        if (k > 0 && !t[k])
            return i;
    }
    return -1;
}