Pointer vs Variable speed in C++

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When you access a “variable”, you look up the address, and then fetch the value.

Remember – a pointer IS a variable. So actually, you:

a) look up the address (of the pointer variable),

b) fetch the value (the address stored at that variable)

… and then …

c) fetch the value at the address pointed to.

So yes, accessing via “pointer” (rather than directly) DOES involve (a bit) of extra work and (slightly) longer time.

Exactly the same thing occurs whether or not it’s a pointer variable (C or C++) or a reference variable (C++ only).

But the difference is enormously small.

Related Contents:

  1. Pointer vs. Reference
  2. Static global variables in C++
  3. What does “dereferencing” a pointer mean?
  4. When to use references vs. pointers
  5. Why use pointers? [closed]
  6. const vs constexpr on variables
  7. Differences between unique_ptr and shared_ptr [duplicate]
  8. Are there benefits of passing by pointer over passing by reference in C++?
  9. Should I use static_cast or reinterpret_cast when casting a void* to whatever
  10. Does the C++ standard mandate poor performance for iostreams, or am I just dealing with a poor implementation?
  11. What is the effect of ordering if…else if statements by probability?
  12. while (1) Vs. for (;;) Is there a speed difference?
  13. What’s the point of const pointers?
  14. Pointer expressions: *ptr++, *++ptr and ++*ptr
  15. What does Visual Studio do with a deleted pointer and why?
  16. Coding Practices which enable the compiler/optimizer to make a faster program
  17. Placement of the asterisk in pointer declarations
  18. Which is more efficient: Return a value vs. Pass by reference?
  19. Meaning of *& and **& in C++
  20. Ternary operator ?: vs if…else
  21. Fastest way to get a positive modulo in C/C++
  22. Why are references not reseatable in C++
  23. Is there a reason why not to use link-time optimization (LTO)?
  24. How to make a for loop variable const with the exception of the increment statement?
  25. Which is faster: x
  26. Big difference (x9) in the execution time between almost identical code in C and C++
  27. c++11 regex slower than python
  28. Why are NULL pointers defined differently in C and C++?
  29. C++: difference between ampersand “&” and asterisk “*” in function/method declaration?
  30. How to access the contents of a vector from a pointer to the vector in C++?
  31. Pointer to incomplete class type is not allowed
  32. difference between a pointer and reference parameter?
  33. What is a dangling pointer?
  34. Will my iPhone app take a performance hit if I use Objective-C for low level code?
  35. Difference between rdtscp, rdtsc : memory and cpuid / rdtsc?
  36. What does ‘dereferencing’ a pointer mean in C/C++?
  37. How to access a local variable from a different function using pointers?
  38. C++ Returning Pointers/References
  39. What’s faster, iterating an STL vector with vector::iterator or with at()?
  40. What does “int* p=+s;” do?
  41. Why do C++ optimizers have problems with these temporary variables or rather why `v[]` should be avoided in tight loops?
  42. Why does C++11 contain an odd clause about comparing void pointers?
  43. Why is there a significant difference in this C++ for loop’s execution time? [duplicate]
  44. Could I ever want to access the address zero?
  45. NULL pointer with boost::shared_ptr?
  46. What is the Fastest Method for High Performance Sequential File I/O in C++?
  47. C++ map vs map performance (I know, “again?”)
  48. Is incrementing a null pointer well-defined?
  49. Why are std::fstreams so slow?
  50. Uses for multiple levels of pointer dereferences?

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