#include <ctype.h> #include <string.h> char* strupr(char* s) { char* d; for (d = s; *d; ++d) *d = (char)toupper((int)*d); return s; } char* strlwr(char* s) { char* d; for (d = s; *d; ++d) *d = (char)tolower((int)*d); return s; }