+#include "ctype.h"
+
+int isalnum(int c)
+{
+ return isalpha(c) || isdigit(c);
+}
+
+int isalpha(int c)
+{
+ return isupper(c) || islower(c);
+}
+
+int isblank(int c)
+{
+ return c == ' ' || c == '\t';
+}
+
+int isdigit(int c)
+{
+ return c >= '0' && c <= '9';
+}
+
+int isupper(int c)
+{
+ return c >= 'A' && c <= 'Z';
+}
+
+int islower(int c)
+{
+ return c >= 'a' && c <= 'z';
+}
+
+int isgraph(int c)
+{
+ return c > ' ' && c <= '~';
+}
+
+int isprint(int c)
+{
+ return isgraph(c) || c == ' ';
+}
+
+int isspace(int c)
+{
+ return isblank(c) || c == '\f' || c == '\n' || c == '\r' || c == '\v';
+}
+
+int toupper(int c)
+{
+ return islower(c) ? (c + ('A' - 'a')) : c;
+}
+
+int tolower(int c)
+{
+ return isupper(c) ? (c + ('A' - 'a')) : c;
+}