How to declare C array of strings

Question

I'm working on a simple lex program for class, and in it I'm creating a very rudimentary symbol table, just an array of strings with a linear scan for search. I've declared it as:

char* identifiers[100];

And I'm using it like so:

found = false;
for (i = 0; i < seen_identifiers; i++) {
    if (!strcmp(identifiers[i], yytext)) {
        printf("Identifier \"%s\" already in symbol table", yytext);
        found = true;
        break;
    }
}
if (!found) {
    printf("identifier: %s\n", yytext);
    seen_identifiers++;
    identifiers[seen_identifiers] = yytext;
}

However I consistently get a segfault at the strcmp call. I'm sure I've screwed up something super simple.

how are you assigning the strings to the array? Can you post that sample code as well? — micmoo
– micmoo, Commented Oct 11, 2009 at 19:20

Steve Gilham · Accepted Answer · 2009-10-11 19:17:51Z

4

seen_identifiers++;
identifiers[seen_identifiers] = yytext;

If seen_identifiers starts at 0, you never assign to identifiers[0] and so the strcmp will fault.

answered Oct 11, 2009 at 19:17

Steve Gilham

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2 Comments

Alex Gaynor Over a year ago

... I feel like an idiot, this is what I get for writing in high level languages all day.

zweihander Over a year ago

Nice observation. I was thinking of null termination.

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