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Pointers and References
This document discusses pointers and references in various programming languages like C, C++, Java, Python and JavaScript. It covers key concepts like pointers, references, lifetime and ownership, copy and move semantics. It also discusses issues with pointers like dangling pointers and null pointers. References in C++ are described as a safer alternative to pointers. The document also discusses pass by reference, object lifetime, resource management strategies, unique ownership, move semantics and borrowing.
Pointers and References
- 1.
- 2. Concepts • Pointers • References(in C++ and other environment) • Lifetime and Ownerships • Copy and Move
- 3. Terms 1. Pointers isobject addresses 2. (C++) Reference is name alias 3. Java uses reference semantics 4. Java object is passed by reference
- 4. Pointers • Pointer (orreference) is an proxy object which refers to another object indirectly.
- 5. Pointers • Pointer (orreference) is an proxy object which refers to another object indirectly.
- 6. Pointers (in C) •Object ID (maybe memory address) • Object Type
- 7. Why we needpointer?
- 8. Issues with CPointers • Dangling Pointers • Resource Leaks • Null Pointers • Weak-typed
- 9. References • (C++)Reference wasan simple syntax sugar of pointers at first.
- 10. References • Reference isa **SAFE** pointer • Must be initialized • Can’t be re-binded • Can’t be null
- 11.
- 12. Reference other thanC++ • Java / C#: • Value & Reference semantics • Automatic resource management • Python / JS: • Everything is reference • CoW • Automatic resource management
- 13.
- 14. Issues with ReferenceSemantics • Resource management & Lifetime control
- 15. Object Lifetime • Global/ static object • Local object • Dynamically created object • Program data (Constant pool etc.)
- 16. Resource Binding Strategy •Heap object with GC • Stack object with RAII • Unique Ownership
- 17. Unique Ownership • Ifowner of resources is destroyed, ALL RESOURCE it owned would be released • Ownership should be unique
- 18.
- 19.
- 20. Move semantics • Zero-copy •Resource uniqueness
- 21.
- 22. Reference Model • Semantics •Value Semantics • Reference Semantics • Move Semantics • Ownership • Borrowing