8 Expressions [expr]

8.9 Relational operators [expr.rel]

The relational operators group left-to-right.
[Example
:
a<b<c means (a<b)<c and not (a<b)&&(b<c).
end example
]
relational-expression:
	shift-expression
	relational-expression < shift-expression
	relational-expression > shift-expression
	relational-expression <= shift-expression
	relational-expression >= shift-expression
The operands shall have arithmetic, enumeration, or pointer type.
The operators < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to) all yield false or true.
The type of the result is bool.
The usual arithmetic conversions are performed on operands of arithmetic or enumeration type.
If both operands are pointers, pointer conversions and qualification conversions are performed to bring them to their composite pointer type.
After conversions, the operands shall have the same type.
Comparing unequal pointers to objects87 is defined as follows:
  • If two pointers point to different elements of the same array, or to subobjects thereof, the pointer to the element with the higher subscript compares greater.
  • If two pointers point to different non-static data members of the same object, or to subobjects of such members, recursively, the pointer to the later declared member compares greater provided the two members have the same access control and provided their class is not a union.
  • Otherwise, neither pointer compares greater than the other.
If two operands p and q compare equal, p<=q and p>=q both yield true and p<q and p>q both yield false.
Otherwise, if a pointer p compares greater than a pointer q, p>=q, p>q, q<=p, and q<p all yield true and p<=q, p<q, q>=p, and q>p all yield false.
Otherwise, the result of each of the operators is unspecified.
If both operands (after conversions) are of arithmetic or enumeration type, each of the operators shall yield true if the specified relationship is true and false if it is false.
An object that is not an array element is considered to belong to a single-element array for this purpose; see [expr.unary.op].
A pointer past the last element of an array x of n elements is considered to be equivalent to a pointer to a hypothetical element x[n] for this purpose; see [basic.compound].