#include <iostream>

void val(int v){
    std::cout << v << std::endl;
    v=v+1;
    std::cout << v << std::endl;
}

int main() {
    int a=5;
    val(std::move(a));
    std::cout << a;
    return 0;
}

/*

std::move is a function in C++ that is used to indicate that an object's ownership
should be transferred to another object. It is typically used to move ownership of
an object from one variable to another, rather than making a copy. This can be 
useful in situations where the original object is no longer needed and the move
can improve performance by avoiding unnecessary copies. For example, std::move
can be used to move ownership of a large object from one container to another,
or to transfer ownership of a dynamically allocated object to a smart pointer.

ex
Here is an example of using std::move to transfer ownership of an object from 
one variable to another:

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#include <iostream>
#include <utility>

int main() {
    std::string original = "Hello, world!";
    std::string moved;

    std::cout << "original: " << original << std::endl;

    moved = std::move(original);

    std::cout << "moved: " << moved << std::endl;
    std::cout << "original: " << original << std::endl;

    return 0;
}
In this example, the string "Hello, world!" is first assigned to the variable
original. The std::move function is then used to transfer ownership of the string
to the variable moved. After the move, the contents of original are undefined, so
the output of the program would look like:

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original: Hello, world!
moved: Hello, world!
original:
Note that std::move does not actually move the data, it just changes the ownership
of the data.
It's important to note that using an object after it has been moved from can lead 
to undefined behavior.