Relational operators, like equality operators, return a boolean value. These operators are used to tell you when an expression is greater than, less than, or equal to another expression.
>= is the greater-than-or-equal operator.
< is the less-than operator.
<= is the less-than-or-equal operator.
The negation greater-than is less-than-or-equal. Some people who've never heard of that find it hard to believe. They think "No way. The opposite of greater than is less than!"
But that's not true. Let's see why. Suppose I say "I am older than you". This means "My age is greater than your age". When would that be false? That is, when would I be lying? Let's assume that ages are integer values.
Certainly, I'm lying if I'm really younger than you. But what if you and I are the same age? In that case, I'm still lying, because if we're the same age, then I can't be older than you. So I'm lying if my age is less than or equal to your age.
We can summarize the negation of these relational operators (plus the equality operators in the following chart.
Operator | Negation |
exprleft == exprright | exprleft != exprright |
exprleft != exprright | exprleft == exprright |
exprleft > exprright | exprleft <= exprright |
exprleft >= exprright | exprleft < exprright |
exprleft < exprright | exprleft >= exprright |
exprleft <= exprright | exprleft > exprright |
Subevaluations | Result |
EVAL[ exprleft ] > EVAL[ exprright ] | EVAL[ exprleft > exprright ] = true |
EVAL[ exprleft ] <= EVAL[ exprright ] | EVAL[ exprleft > exprright ] = false |
EVAL[ exprleft ] >= EVAL[ exprright ] | EVAL[ exprleft >= exprright ] = true |
EVAL[ exprleft ] < EVAL[ exprright ] | EVAL[ exprleft >= exprright ] = false |
EVAL[ exprleft ] < EVAL[ exprright ] | EVAL[ exprleft < exprright ] = true |
EVAL[ exprleft ] >= EVAL[ exprright ] | EVAL[ exprleft < exprright ] = false |
EVAL[ exprleft ] <= EVAL[ exprright ] | EVAL[ exprleft <= exprright ] = true |
EVAL[ exprleft ] > EVAL[ exprright ] | EVAL[ exprleft <= exprright ] = false |
The right column says what the evaluation's result is based on the evaluation of the left and right operand from the left column.