4.1.0.main.c

#include <stdio.h>
#define MAXLINE 1000 /*maximum input line length*/

int getline(char line[], int max);
int strindex(char source[], char searchfor[]);

char pattern[] = "ould"; /*pattern to search for*/

/*find all lines matching pattern*/
int main() {
    char line[MAXLINE];
    int found = 0;

    while (getline(line, MAXLINE) > 0) {
        if (strindex(line, pattern) >= 0) {
            printf("%s", line);
            found++;
        }
    }

    return found;
}

/*getline: get line into s, return length*/
int getline(char s[], int lim) {
    int c, i;

    i = 0;
    while (--lim > 0 && (c=getchar()) != EOF && c != '\n')
        s[i++] = c;
    if (c == '\n')
        s[i++] = c;
    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] != '\0' ; i++) {
        for (j = i, k = 0; t[k] != '\0' && s[j] == t[k]; j++, k++)
            ;
        if (k > 0 && t[k] == '\0')
        return i;
    }
    return -1;
}