Apex Variables
A variable is a named value holder in memory. In Apex, local variables are declared with Java-like syntax.
The name we choose for a variable is called an identifier. Identifiers can be of any length but they must begin with an alphabet. The rest of the identifiers can include digits also.
- Operators and spaces are not allowed.
- We can’t use any of the apex reserved keywords when naming variables, methods or classes.
- Keywords are the words that are essential for the Apex language.
| Integer i_a; 🗸 | Integer i 2; ☓ |
| Integer _ia; ☓ | Integer i$2; ☓ |
| Integer ia_; ☓ | Integer $i2; ☓ |
| Integer i2; 🗸 | Integer $_i_2; ☓ |
Apex Constants
Apex Constants are the variables whose values don’t change after being initialized once.
Constants can be defined using the final keyword. Constants can be assigned almost once either in the declaration itself or with a static initialization method if the constant is defined in a class.
final integer a =5;
Note: We cannot use the final keyword in the declaration of a class or a method because in apex classes and methods are by-default final and cannot be overridden or inherited without using the virtual keyword.
Apex Literals
Integer i = 123;
String str = ‘abc’;
Expression:
An Expression is a combination made up of variables, operators and method invocation that evaluates to a single value.
Datatypes:
Apex is a strongly typed language i.e we must declare the datatype of a variable when we first refer to it. All apex variables are initialized to null by default.
Expression:
An Expression is a combination made up of variables, operators and method invocation that evaluates to a single value.
Datatypes:
Apex is a strongly typed language i.e we must declare the datatype of a variable when we first refer to it. All apex variables are initialized to null by default.
