C++ Language/Expressions/ChainOfAssignment

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C++ Language
  1. Overview
  2. Preprocessing
    1. Macros
    2. Tokenization
    3. Preprocessing Strings
    4. Compile-time Constants
    5. Compile-time Assertions
    6. Conditional-Compilation
  3. Namespace
    1. Namespace Shortcuts
    2. Nesting
    3. Splitting across Files
    4. Named and Unnamed
  4. Type
    1. Hungarian Prefixes
    2. Boolean
    3. Literals
    4. Bitwise Representation
    5. Max Value
    6. Conversion
    7. Enumeration
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    9. Variant
    10. RTTI: RunTime Type Information
  5. Variables
    1. Lifetime and Scope
    2. Initialization
    3. Uniform Initialization
    4. Initialize without Constructor
    5. Decomposing-Auto
    6. Define at Same Time as Type
  6. Indirection
    1. Pointers
    2. Typed NULL
    3. Arrays
    4. Reference Variables
    5. Rvalue-References
    6. Smart Pointers
  7. Expressions
    1. Precedence
    2. Chain of Assignment
  8. Program Flow
    1. Loops
    2. The break Statement
    3. Return Value
    4. Parameters
    5. Function Overloading
    6. Function-Pointer
    7. Deprecating a Function
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    8. Operator Overloading
    9. Nested Classes
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    11. Low-Level C Structures
  10. Templates
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    4. Template-Parameters
    5. Traits
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  11. Error Handling
    1. Returning an Error Code
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  12. Standard Libraries
    1. C-Runtime
    2. STL: Standard Template Library
    3. Strings
    4. IOStreams
    5. Filesystem Access
    6. Multithreading
    7. RNG: Random Number Generator
  13. Obsolete Features

The "compound assignment" iVar += 2; is an abbreviation for iVar = iVar + 2;.

Programmers usually think about += only in terms of its effect (changing the value stored in iVar's memory), but that expression does also evaluate to a value. In fact, it evaluates to a "lvalue" which means that iVar+=2 is allowed to occur on the left-hand-side of some other assignment (although it would be weird to do so).

Additional information about lvalues (includes interactive examples)

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