const unsigned char* n1 = (const unsigned char*)s1.c_str();
const unsigned char* n2 = (const unsigned char*)s2.c_str();
for (; *n1 && *n2; n1++, n2++)
const unsigned char* n1 = (const unsigned char*)s1.c_str();
const unsigned char* n2 = (const unsigned char*)s2.c_str();
for (; *n1 && *n2; n1++, n2++)