How can I count the number of occurrences of the character '/' in a C string?

Question

How can I count the number of occurrences in a C string of / ?

I can do this:

int countSlash(char str[])
{
    int count = 0, k = 0;
    while (str[k] != '\0')
    {
          if (str[k] == '/')
              count++;
          k++;
    }
    return count;
}

But this is not an elegant way; any suggestions on how to improve it?

Answer 1

strchr would make a smaller loop:

ptr = str;

while ((ptr = strchr(ptr '/')) != NULL)
    count++, ptr++;

I should add that I don't endorse brevity for brevity's sake, and I'll always opt for the clearest expression, all other things being equal. I do find the strchr loop more elegant , but the original implementation in the question is clear and lives inside a function, so I don't prefer one over the other, so long as they both pass unit tests.

Answer 2

Yours is good enough. Maybe, this would look prettier to some:

int countSlash(char * str)
{
    int count = 0;
    for (; *str != 0; ++str)
    {
        if (*str == '/')
            count++;
    }
    return count;
}

Answer 3

Generic interface, obvious approach, appropriate types and purely idiomatic expressions:

size_t str_count_char(const char *s, int c)
{
    size_t count = 0;

    while (s && *s)
         if (*s++ == c)
             ++count;

    return count;
}

Oli Charlesworth would probably raise concerns regarding assignments and conditionals on the same line, but I think it's fairly well hidden ;-)

Answer 4

This will also work:

int count=0;
char *s=str;
while (*s) count += (*s++ == '/');