Nick Nick 10 10 silver badges 19 19 bronze badges. Arrays are most definitely not pointers. Arrays decay or are implicitly converted into pointers when used on the right-hand side of the assignment operator and when passed as a function argument. Pointers being faster than arrays is coming from the following example. But there are two things: It's not pointers which are fast, it's algorithm using them for optimization.
Optimizer can easily perform this kind of optimization automatically, so you probably end up with the same generated code anyway. Paul, yes, this is mentioned in the answer, this is oversimplified example and this is explained — unkulunkulu. Sign up or log in Sign up using Google.
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Now live: A fully responsive profile. Linked Related Hot Network Questions. Question feed. Stack Overflow works best with JavaScript enabled. For the most cases in a modern compiler, however, it just gives the compiler one less register to work with, and the compilers these days are pretty darn good at figuring out what to put in a register, and what to not put in a register. On x86, this would almost certainly cause more problems than it solves as there are only a few 7 at the very most freely usable registers in x Even if almost every line is accessing the global variable it's unlikely to give any enormous benefits then either, since the compiler will be able to load the global pointer at the beginning of the code and then operate on it from then on.
Compilers these days are pretty good at assigning registers the right way, and given a choice, I'd prefer to use the compiler to figure out which register to use when. However, it does work to use global register variables in gcc: Code:. I use pass structs by pointers. That can save up some space. Not sure if this is efficient though.
Originally Posted by broli My homepage Advice: Take only as directed - If symptoms persist, please see your debugger Linus Torvalds: "But it clearly is the only right way. The fact that everybody else does it some other way only means that they are wrong". Originally Posted by iMalc. Don't use the register keyword EVER! In almost all compilers used nowdays it does nothing whatsoever, and in the ones where is doesn't do nothing you will almost cetainly only make things worse - even if you consider yourself an expert programmer!
Whether you create the array using method 1 or method 2, you interact with the array in the same way that you would in a Java program. You use the array index notation to access and work with individual cells in the array. If you created the array using method 1 above, the array will vanish automatically when you exit the scope where it was created.
If you created the array via the new operation, you will need to explictly make the array go away when you are done with it by using the delete[] operator:.
As an alternative to using the traditional array index notation, you can also use a pointer to access and interact with the elements in an array. This pointer points to the first element in the array. You can dereference that pointer to access the array element. Pointer variables that point into an array can also be moved around in the array via the pointer increment and decrement operations.
Here is some code that uses a pointer to initialize the contents of an array. Note the use of the! These lecture notes are going to take us through two iterations of a program that performs a simple task.
We are going to write a program that can read a list of integers from a text file, sort those integers with an elementary sorting algorithm, and then write the sorted list to a second text file.
In the first iteration we will write the program using conventional array notation. In the second iteration we will accomplish the same task working solely with pointers. If you are using Visual Studio, this code will work as is, as long as you make sure the text file named numbers. On Xcode, you will have to replace the file name in the open function with the full path to the file in question. The results were a bit surprising at least to me! I expected pointer access to be slightly faster, but apparently,it is not so and sometimes pointer usage is a bit slower!
Most likely there is more to it, and next I intend to take a look at boundary checks of. Is it possible that the boundary checks were optimized-away in this case? After some digging, I read through some code in.
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