find...

find.c

#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{
    if (argc < 2) return -1;

    FILE *fp = fopen(argv[1], "r");

    char linebuf[1024], head[] = "answer=\"";
    while (fgets(linebuf, sizeof(linebuf), fp) != NULL) {
        char *beg = linebuf;
        while ((beg = strstr(beg, head)) != NULL) {
            beg += sizeof(head) - 1;        // Jump 'answer="'
            char *end = strstr(beg, "\"");  // Expect answer=".*" in one line (end shouldn't be null)
            printf("%.*s\n", (int)(end - beg), beg);
            beg = end + 1;
        }
    }

    return 0;
}