Defined in header <math.h> #define isinf(arg) /* implementation defined */ (since C99) Determines if the given floating point number arg is positive or negative infinity. The macro returns an integral value. FLT_EVAL_METHOD is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that. Parameters arg - floating point value Return value Nonzero integ

Defined in header <math.h> #define isgreaterequal(x, y) /* implementation defined */ (since C99) Determines if the floating point number x is greater than or equal to the floating-point number y, without setting floating-point exceptions. Parameters x - floating point value y - floating point value Return value Nonzero integral value if x >= y, ​0​ otherwise. Notes The built-in operator>= for floating-point numbers may raise FE_INVALID if one or

Defined in header <math.h> #define isgreater(x, y) /* implementation defined */ (since C99) Determines if the floating point number x is greater than the floating-point number (y), without setting floating-point exceptions. Parameters x - floating point value y - floating point value Return value Nonzero integral value if x > y, ​0​ otherwise. Notes The built-in operator> for floating-point numbers may set FE_INVALID if one or both of the argume

Defined in header <ctype.h> int isgraph( int ch ); Checks if the given character has a graphical representation, i.e. it is either a number (0123456789), an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz), or a punctuation character(!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~), or any graphical character specific to the current C locale. The behavior is undefined if the value of ch is not representable as unsigned char and is no

Defined in header <math.h> #define isfinite(arg) /* implementation defined */ (since C99) Determines if the given floating point number arg has finite value i.e. it is normal, subnormal or zero, but not infinite or NaN. The macro returns an integral value. FLT_EVAL_METHOD is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that. Parameters arg - floa

Defined in header <ctype.h> int isdigit( int ch ); Checks if the given character is a numeric character (0123456789). The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character to classify Return value Non-zero value if the character is a numeric character, zero otherwise. Notes isdigit and isxdigit are the only standard narrow character classification functions that are not affected

Defined in header <ctype.h> int iscntrl( int ch ); Checks if the given character is a control character, i.e. codes 0x00-0x1F and 0x7F. The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character to classify Return value Non-zero value if the character is a control character, zero otherwise. Example #include <stdio.h> #include <ctype.h> #include <locale.h> int ma

Defined in header <ctype.h> int isblank( int ch ); (since C99) Checks if the given character is a blank character in the current C locale. In the default C locale, only space (0x20) and horizontal tab (0x09) are classified as blank. The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character to classify Return value Non-zero value if the character is a blank character, zero otherwise.

Defined in header <ctype.h> int isalpha( int ch ); Checks if the given character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), or a lowercase letter (abcdefghijklmnopqrstuvwxyz). In locales other than "C", an alphabetic character is a character for which isupper() or islower() returns true or any other character considered alphabetic by the locale. In any case, iscntrl(), isdigit(), ispunct() and isspace() will return false for th

Defined in header <ctype.h> int isalnum( int ch ); Checks if the given character is an alphanumeric character as classified by the current C locale. In the default locale, the following characters are alphanumeric: digits (0123456789) uppercase letters (ABCDEFGHIJKLMNOPQRSTUVWXYZ) lowercase letters (abcdefghijklmnopqrstuvwxyz) The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character