Operators

Operators are the base commands each programming language is built on. They provide ability to perform basic mathematical and logical operations.

Requirements

To understand this article, you should read the following articles:

• Variables

Terms

Operand An operand is any value given to an operator.

Expression An expression is basically any code that returns a value. Read expression for more information.

Unary Operator An unary operator is an operator that requires only one operand.

Unary operation: *operator* expression

Binary Operator A binary operator is an operator that requires two operands.

Binary operation: expression *operator* expression

Operators

Assignment Operators

Assignment operators are used to assign values to a variable. OFP's scripting language provides only one assignment operator.

Assignment: identifier = expression

Example 1:

a = b

You might think that this operator compares a and b, but that is not the case. = simply sets the left value to be the right one. Other assignment operators like , that can be found in other programming languages do not exist in SQF/SQS.

Example 2:

a = b * c

Arithmetic Operators

Remember arithmetic operations from school? These work just the same way. All operands of arithmetic operations must be Numbers. Arithmetic operations always return a Number.

Note

See also Math Commands.

Logical Operators

Logical operators evaluate Boolean values. All operands of logical operations are Booleans. A logical operation always returns a Boolean.

The Not-operator always returns the inverse Boolean value. If a Boolean a is true, !a returns false and vice versa.

• And only returns true if both operands are true
• Or returns true if one or both operands are true

There is no Xor, Nor and Nand operator. Those can be simulated using the basic operators though:

• Xor returns true if exactly one of both values is true
• Nor returns true if none of both values is true
• Nand returns true if not both values are true at the same time

Comparison Operators

Comparison operators compare two values. Operands of comparisons may be of type Number, Side, String, Object, Group, Structured Text, Config, Display or Control for and , and Number for . Comparisons always return a Boolean: true if the comparison matches, false if not.

Note

Array Operators

The scripting language offers own operators to deal with arrays. All operands, of course, have to be of type Array. The return value of an array operation is an Array.

Normally arrays are assigned by reference. That means, if you assign array a to array b and change a afterwards, also b is changed. Use the copy operator to avoid this otherwise useful feature.

Example 1:

_arrayA = [1,2];
_arrayB = _arrayA;
_arrayA set [0,5];

// _arrayA => [5,2]
// _arrayB => [5,2]

Example 2:

_arrayA = [1,2];
_arrayB = +_arrayA;
_arrayA set [0,5];

// _arrayA => [5,2]
// _arrayB => [1,2]

• + adds the second operand on the end of the first operand
• - removes all elements of the second operand from the first operand

Example 1:

_arrayA = [1,2];
_arrayB = [3,2,4];

_arrayC = _arrayA + _arrayB;

// _arrayC => [1,2,3,2,4]

Example 2:

_arrayA = [1,2,3,2,4];
_arrayB = [2,3];

_arrayC = _arrayA - _arrayB;

// _arrayC => [1,4]

String Operators

The scripting language offers one single string operator to concatenate strings. Both operands must be Strings. The return value of a string operation is a String.

• + adds the second operand on the end of the first operand

Example:

_stringA = "Hello ";
_stringB = "World!";

_stringC = _stringA + _stringB;

// _stringC => "Hello World!"

Config Operators

Example:

class B_Soldier_F;
class MySoldier: B_Soldier_F
{
    RespawnItems[] += {"FirstAidKit"}; //Adds additional FAK
};

/*
    Original RespawnItems[] array in config viewer:
    RespawnItems[] = {"FirstAidKit"};

    Modified RespawnItems[] array in config viewer:
    RespawnItems[] = {"FirstAidKit","FirstAidKit"};
*/

Order of Precedence

See Order of Precedence.

See Also

• SQF Syntax
• SQS Syntax