Searching text file for matching string

Question

I'm a complete amateur when it comes to C and I was having some trouble trying to write this piece of code. I want it to check the text file for any line that matches the given string.

For example, if "stackoverflow" was in the text file and the string I was entered was "www.stackoverflow.com" it should return a positive match.

But currently it is searching for the string inside of the text file, which is the opposite of what I want. I would appreciate any hints/tips!

int Check(char *fname, char *str) {
FILE *file;
int i = 1;
int r = 0;
char temp[1000];

if((file = fopen(fname, "r")) == NULL) {
    return(-1);
}

while(fgets(temp, 1000, file) != NULL) {

    if((strstr(temp, str)) != NULL) {
        printf("Host name found on line: %d\n", i);
        printf("\n%s\n", str);
        r++;
    }
    i++;
}

if(r == 0) {
    printf("\nHost name not blocked.\n");
}

if(file) {
    fclose(file);
}
return(0);
}

Hello, welcome to StackOverflow! Have you tried switching `strstr(temp, str)` with `strstr(str, temp)`? — John Odom, Nov 20 '14 at 20:14
Yes, but when I tried that I would get no results even if the strings I was comparing were identical. — Piglet, Nov 20 '14 at 20:16
Please keep in mind `fgets` captures a trailing newline (`\n`); you may need to strip that off yourself. — Ruud Helderman, Nov 20 '14 at 20:17
Do you have whitespace (line ending chars like `\r` and/or `\n`) at the end of one or both of the strings you're comparing? — Brian Cain, Nov 20 '14 at 20:18
@Piglet I'm glad you got it working :). You should post your answer then mark it as accepted so that other users would see it. — John Odom, Nov 21 '14 at 15:04

score 1 · Answer 1 · answered Mar 26 '15 at 11:08

1

Why not use getline() to get a line-by-line buffer and then do a strstr() in that buffer ?

answered Mar 26 '15 at 11:08

Paul Praet

1,367
14
25

Probably because [it is not a C Standard Library function](http://stackoverflow.com/questions/13112784/undefined-reference-to-getline-in-c). – Jongware Mar 26 '15 at 11:24

Searching text file for matching string

1 Answers1