Boolean types
A Boolean variable can be used to hold the integer values 0 or 1, 
or the literals true or false
,
which are implicitly promoted to the integers 1 and 0 respectively,
whenever an arithmetic value is necessary. The Boolean type is unsigned
and has the lowest ranking in its category of standard unsigned integer
types; it may not be further qualified by the specifiers signed, unsigned, short,
or long. In simple assignments, if the left operand
is a Boolean type, then the right operand must be either an arithmetic
type or a pointer.
Boolean type is a C99 feature. To
declare a Boolean variable, use the _Bool type specifier. 
The
token bool is recognized as a keyword in C only when
used in a vector declaration context and vector support is enabled. 
To declare a Boolean
variable in C++, use the bool type specifier. The
result of the equality, relational, and logical operators is of type bool:
either of the Boolean constants true or false.
_Bool f(int a, int b)
{
return a==b;
}
