D provides the binary relational operators that are described in the following table for use in your programs. These operators all have the same meaning that they do in ANSI C.
Table 2.8 D Relational Operators
Operator | Description |
|---|---|
| Left-hand operand is less than right-operand |
| Left-hand operand is less than or equal to right-hand operand |
| Left-hand operand is greater than right-hand operand |
| Left-hand operand is greater than or equal to right-hand operand |
| Left-hand operand is equal to right-hand operand |
| Left-hand operand is not equal to right-hand operand |
Relational operators are most frequently used to write D
predicates. Each operator evaluates to a value of type
int, which is equal to one if the condition
is true, or zero if it is
false.
Relational operators can be applied to pairs of integers,
pointers, or strings. If pointers are compared, the result is
equivalent to an integer comparison of the two pointers
interpreted as unsigned integers. If strings are compared, the
result is determined as if by performing a
strcmp() on the two operands. The following
table shows some example D string comparisons and their results.
D string comparison | Result |
|---|---|
|
Returns 1 ( |
|
Returns 1 ( |
|
Returns 0 ( |
Relational operators can also be used to compare a data object associated with an enumeration type with any of the enumerator tags defined by the enumeration. Enumerations are a facility for creating named integer constants and are described in more detail in Section 2.13, “Type and Constant Definitions”.