isalnum() | isalpha() | iscntrl() | isdigit() | isgraph() | islower() | isprint() | ispunct() | isspace() | isupper() | isxdigit() | tolower() | toupper() |
acos() | asin() | acosh() | asinh() | atan() | atanh() | sin() | cos() | tan() | sinh() | cosh() | atan2() | exp() | fabs() | ceil() | floor() | sqrt() | log() | log10() | pow() |
fclose() | clearerr() | feof() | ferror() | fflush() | fopen() | printf() | scanf() | getc() | putc() | fread() | fwrite() |