typedef unsigned int size_t;
typedef unsigned char uchar;

size_t Strlen(const char* str) {
    int i = 0;
    for (const char* p = str; p && *p; p++, i++);
    return i;
}
// first element that in { c | c = str - (str ∩ strSet) }
size_t Strspn(const char* str, const char* strSet) {
    for (const char* p = str; p && *p; p++)
        for (const char* q = strSet; q; q++)
        {
            if (!*q) return p - str;
            else if (*q == *p) break;
            else continue;
        }

    return 0;
}
// first element that in { c | c = str ∩ strSet }
size_t Strcspn(const char* str, const char* strSet)
{
    for (const char* p = str; p && *p; p++)
        for (const char* q = strSet; *q && q; q++)
            if (*q == *p) return p - str;
    return 0;
}

char* Strtok(char* token, const char* delimit)
{
    const char* empty = "";
    static char* last;
    char* e = (char*)delimit;
    char* s;
    token ? s = token : s = last;
    s += Strspn(s, e);  
    if (!*s) {
        last = (char*)empty;
        return NULL;
    }
    e = s + Strcspn(s, e);
    if (*e) *e++ = '\0';
    last = e;
    return s;
}