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improved code.
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Junius L
Junius L
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UPDATE

I have rewritten the code to get rid of allocating memory inside strstr, as advised by ratchet freak and Jerry Coffin.

char    *my_strstr(const char *haystack, const char *needle)
{
    size_t  needle_len;

    needle_len = strlen(needle);
    while (*haystack)
    {
        if (*haystack == *needle)
        {
            if (!strncmp(haystack, needle, needle_len))
                    return ((char *)haystack);
        }
        haystack++;
    }
    return (NULL);
}

UPDATE

I have rewritten the code to get rid of allocating memory inside strstr, as advised by ratchet freak and Jerry Coffin.

char    *my_strstr(const char *haystack, const char *needle)
{
    size_t  needle_len;

    needle_len = strlen(needle);
    while (*haystack)
    {
        if (*haystack == *needle)
        {
            if (!strncmp(haystack, needle, needle_len))
                    return ((char *)haystack);
        }
        haystack++;
    }
    return (NULL);
}
edited tags; edited title
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200_success
200_success
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recreating Recreating strstr in cC

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Junius L
Junius L
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  • 1
  • 9
  • 13

recreating strstr in c

I'm trying to recreate strstr in c, my code works but I think it is too long, and it needs some improvement.

#include <stdlib.h>

static int      find_str_indx(char *str, int index, char *str_to_find)
{
    int i;
    int temp;
    int found_index;

    while (str[index] != '\0')
    {
        if (str[index] == *str_to_find)
        {
            temp = index;
            i = 0;
            found_index = index;
            while (str_to_find[i] != '\0' && str[index] != '\0')
            {
                if(str_to_find[i] != str[index])
                    found_index = -1;
                i++;
                index++;
            }
            if (found_index == -1)
                index = temp;
        }
        index++;
    }
    return (found_index);
}

char    *my_strstr(char *str, char *to_find)
{
    char    *found_str;
    int     found_index;
    int     i;

    found_str = (char*)malloc(sizeof(found_str));
    found_index = find_str_indx(str, 0, to_find);
    if (found_index != -1)
    {
        i = 0;
        while (str[found_index] != '\0')
        {
            found_str[i] = str[found_index];
            found_index++;
            i++;
        }
    }
    else
        found_str = NULL;
    return (found_str);
}