#include size_t strlen (const char *str) { size_t i; for (i = 0; *str!=0; str++) i++; return i; } int strcmp(const char *pStr1, const char *pStr2) { char c1, c2; int v; do { c1 = *pStr1++; c2 = *pStr2++; /* the casts are necessary when pStr1 is shorter & char is signed */ v = (unsigned int)c1 - (unsigned int)c2; } while ((v == 0) && (c1 != '\0')); return v; }