pollution: c
int isalnum(int c); 

pollution: c
int isalpha(int c); 

pollution: c
int isascii(int c); 

pollution: c
int isblank(int c); 

pollution: c
int iscntrl(int c); 

pollution: c
int isdigit(int c); 

pollution: c
int isgraph(int c); 

pollution: c
int islower(int c); 

pollution: c
int isprint(int c); 

pollution: c
int ispunct(int c); 

pollution: c
int isspace(int c); 

pollution: c
int isupper(int c); 

pollution: c
int isxdigit(int c); 

pollution: c
int tolower(int c); 

pollution: c
int toupper(int c);