Expression types

The type of an expression is always identical to the data type of the result value. There are three types of expression, corresponding to the three data types:

• arithmetic expressions

• logical or Boolean expressions

• string expressions

The type of a simple expression is determined by the operator that links together the base terms. The table below lists simple expressions and their components:

Type	Operators	Base terms	Result data type
Arithmetic expression	Arithmetic	Numbers Variable names Function calls	Integer
Relational expression	Relational	Numbers Boolean constants String literals Variable names Function calls	Boolean
Logical or Boolean expression	Logical	Boolean constants Variable names Function calls	Boolean
String expression	Concatenation	String literals Variable names Function calls	String

For complex expressions, the data type of the result, and thus of the expression, is determined by the last operator to be evaluated. The order of precedence for operators and the way in which expressions are evaluated is described in the next section.