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#include "my_strspn.h" int is_in(char c, const char *accept) { for (; *accept && *accept != c; accept++) { continue; } return *accept != '\0'; } size_t my_strspn(const char *s, const char *accept) { if (s == NULL || *s == '\0') { return 0; } size_t res; for (res = 0; *s && is_in(*s, accept) != 0; res++, s++) { continue; } return res; }