# Var

Deutsch (de) English (en) español (es) suomi (fi) français (fr) русский (ru) 中文（中国大陆）‎ (zh_CN)

Var is a keyword that is used for two different purposes:

• signify the start of a variable definition section
• make a function or procedure parameter be passed by reference instead of passed by value

## Variable Definition

Var is used to mark the section where variables and their data types are declared. Variables are typically declared at the beginning of a program, procedure, function or unit.

var
age: integer;

If you are planning to use various variables of the same type, they can be grouped so they share the same type definition. The variables must be separated by a comma.

var
FirstName, LastName, address: string;

## Pass by Reference

When used before a parameter of a procedure or function var indicates that the parameter is a variable parameter. A variable parameter can be used to receive data from, as well as send data to, a procedure or function:

procedure foo( var v1: sometype; out v2: sometype; const v3: sometype )
begin
v1 := v1 + v3; // input and return value
v2 := v3;      // only return value
v3 := myconst; // immutable... only input
end;