1 # include <stdio.h> 2 # include <ctype.h> 3 4 # define reg register 5 6 # define makelower(c) (isupper(c) ? tolower(c) : c) 7 8 /* 9 * Compare strings: s1>s2: >0 s1==s2: 0 s1<s2: <0 10 */ 11 12 strcmp(s1, s2) 13 reg char *s1, *s2; { 14 15 while (makelower(*s1) == makelower(*s2)) { 16 if (*s1 == '\0') 17 return 0; 18 s1++, s2++; 19 } 20 return *s1 - *s2; 21 } 22