int vs const int&, And when I use it

const int vs #define
const pointer c
const int c#
int *const ptr = &x
int and int
arduino define vs int
const int size = 5
int a(10 means)

You should generally use references if you plan on continuing to use the value you are passing into a function after that function completes. As you have highlighted, sometimes it is more costly to pass a reference. This can happen if your data is very small (you normally wouldn't bother passing integers as arguments), or if you have an opportunity to move the contents of the variable (though this can be a more complicated topic).

Using references allows you to avoid copying data while still guaranteeing that the argument is valid, since unlike with pointers there is no null reference. References give you the opportunity of allowing the function to mutate the contents of your variable, or with const references you can prevent a function from modifying the variable you pass in. In general you should prefer to use references over pointers when you don't need features only available with a pointer, and prefer const references over references when you don't need mutation.

Difference between const int*, const int * const, and , integer. Effectively, this implies that the pointer is pointing to a value that shouldn't be changed. int * const ptr - ptr is a constant pointer to int; const int * const ptr - ptr is a constant pointer to const int; Now the first const can be on either side of the type so: const int * ptr equal to int const * ptr; const int * const ptr equal to int const * const ptr; If you want to go really crazy you can do things like this: int ** ptr - ptr is a pointer to pointer to int; int ** const ptr - ptr is a const pointer to a pointer to an int


Using (const type& var) you will ensure that the object should not be modified, and only leave acces to constant methods. Using pointer does not guarantee that an object is passed (or an array of objects). Could you explain more the third question?

What is the difference between const int*, const int , not use any RAM. The value is used as the actual value wherever it is referenced, just like #define. const int is identical to int const, as is true with all scalar types in C. In general, declaring a scalar function parameter as const is not needed, since C's call-by-value semantics mean that any changes to the variable are local to its enclosing function.


Question 3 answer: If I understand you correctly, passing value, that is not reference or pointer to the function that takes reference will give this function direct access to this variable, or also fields of the actual value that you passed to this function. Example:

void foo(int& ref)
{
    ref = 5;
}

void bar(int non_ref)
{
    non_ref = 0;
}
int main()
{
    int integer_value = 1;
    foo(integer_value);
    bar(integer_value);

    return 0;
}

The first function will affect passed value, but the second won't, cause the operation of this function applied to copy of passed value.

When to use int, const int or define, The difference is the "const" keyword. In your first example, "size" is not a constant. This allows the size to be redefined and changed. It's nearly as type safe as const int (every bit as type safe in C++11). It provides a natural way of grouping related constants. You can even use them for some amount of namespace control. So in an idiomatic C++ program, there is no reason whatsoever to use #define to define an integer constant.


Diffference between #define and const in C?, Basically, an int is read/write and a const int is read only. You use a const int for something that never changes value, such as a pin number. The advantage is  Arduino boards have microcontrollers with notoriously small amounts of RAM. The Uno only has 2,048 bytes of static RAM available for your program to store variables. So when you need to keep non-changing variables out of RAM which is best to use const or #define? What is #define #define is often misunderstood because it isn’t […]


Is there a difference between "const int" and "int" in C++?, When should you use a class vs a struct in C++?. 21,464 Views · What are the differences between int& const, int const&, const& int and const int& in C++?. const int is identical to int const, as is true with all scalar types in C. In general, declaring a scalar function parameter as const is not needed, since C’s call-by-value semantics mean that any changes to the variable are local to its enclosing function.


Int vs Const int : arduino, const.c. The trick is to read the declaration backwards (right-to-left):. const int a = 1; // read as "a is an integer which is constant". int const a = 1;  int const * const Constant4 declares that Constant4 is constant pointer to a constant integer. ‘const’ applies to whatever is on its immediate left (other than if there is nothing there in which case it applies to whatever is its immediate