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Notes Comparison Operators
As their name suggests, comparison operators compare operands. The result is always either true,
if the comparison is truthful, or false, otherwise.
Operands to the comparison operators can be both numeric, both string, or one numeric and one
string. The operators check for truthfulness in slightly different ways based on the types and
values of the operands, either using strictly numeric comparisons or using lexicographic (textual)
comparisons. Table 2.4 outlines when each type of check is used.
Table 2.4: Type of Comparison Performed by the Comparison Operators

First operand Second operand Comparison
Number Number Numeric
String that is entirely numeric String that is entirely numeric Numeric
String that is entirely numeric Number Numeric
String that is not entirely numeric Number Lexicographic
String that is entirely numeric String that is not entirely numeric Lexicographic
String that is not entirely numeric String that is not entirely numeric Lexicographic

One important thing to note is that two numeric strings are compared as if they were numbers. If
you have two strings that consist entirely of numeric characters and you need to compare them
lexicographically, use the strcmp ( ) function.
The comparison operators are:
Equality (==)
If both operands are equal, this operator returns true; otherwise, it returns false.

Identical (===)
If both operands are equal and are of the same type, this operator returns true; otherwise, it returns
false. Note that this operator does not do implicit type casting. This operator is useful when
you do not know if the values you are comparing are of the same type. Simple comparison may
involve value conversion. For instance, the strings “0.0” and “0” are not equal. The == operator
says they are, but === says they are not.

Inequality (! = or <>)
If both operands are not equal, this operator returns true; otherwise, it returns false.
Not identical (! ==)
If both operands are not equal, or they are not of the same type, this operator returns true;
otherwise, it returns false.
Greater than (>)
If the left-hand operator is greater than the right-hand operator, this operator returns true;
otherwise, it returns false.
Greater than or equal to (>=)

If the left-hand operator is greater than or equal to the right-hand operator, this operator returns
true; otherwise, it returns false.
Less than (<)

If the left-hand operator is less than the right-hand operator, this operator returns true; otherwise,
it returns false.

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