pointer

[ishti alam]

Write your question here.
as i am a very new student in programming i want to know how can i write code in pointer.

[3qX21hU5]

int number = 5;
int* myPointer = &number;   // Creates a pointer that points to the variable number

cout << *myPointer;   // Dereferences the pointer to get the value and prints it 

What exactly don't you understand about pointers? We need more details to be able to help you out. I assume this is for a assignment on pointers but generally when using C++ you will want to use smart pointers when possible.

Like std::unique_ptr<>()

[Josue Molina]

Zereo, I think you're losing the crap out of him with your post. :-P

He's asking how he can write code in pointer.

I don't think he knows what a pointer is!

[ne555]

const char *code = "int main(){}";

[3qX21hU5]

Lol

[JLBorges]

> how can i write code in pointer.

We don't write code in pointer. We write code normally, as some kind of a function.

#include <iostream>
#include <string>
#include <cctype>

void say_hello( const std::string& name )
{
    std::cout << "hello " << name << "!\n" ;
}

void print_uc( const std::string& name )
{
    for( char c : name ) std::cout << char( std::toupper(c) ) ;
    std::cout << '\n' ;
}

Once we have a function, we can create pointers that point to the function.
In much the same way as: once we have an int, we can create pointers that point to the int.

For instance:

int main()
{
    const std::string n = "ishti alam" ;

    auto ptr = &say_hello ; // ptr points to function 'say_hello'
    ptr(n) ; // call the function that ptr points to

    ptr = &print_uc ; // ptr now points to function 'print_uc'
    ptr(n) ; // call the function that ptr points to

    ptr = nullptr ;

    // etc
}

[LB]

I interpreted it to mean writing op codes into a buffer, using the OS' native API function to make the memory executable, and then executing the memory by casting it to a function and calling it. Isn't that writing code in pointer?

[3qX21hU5]

To make it even more complicated shouldn't you be using std::function to be passing around a function instead of a function pointer? I am still quite new to #include <functional> and functional programming in general so this is actually kind of a serious question. Is there benefits to using a function pointer over std::function? Or the other way around?

For example

#include <iostream>
#include <string>
#include <functional>

using namespace std;
using namespace std::placeholders;

void say_hello( const std::string& name )
{
    std::cout << "hello " << name << "!\n" ;
}

void print_uc( const std::string& name )
{
    for( char c : name ) std::cout << char( std::toupper(c) ) ;
    std::cout << '\n' ;
}

class MyStuff
{
    public:
        void printGoodbye(const std::string& name)
        {
            std::cout << "Goodbye " << name << "!\n";
        }
};

int main()
{
    const std::string n = "ishti alam";
    MyStuff goodClass;

    // Create the function object to hold the function
    std::function<void(const std::string&)> stuff = say_hello;

    // Call that function object
    stuff(n);

    // Well I am bored with that funtion time for a new one.
    stuff = print_uc;

    // Call the new one.
    stuff(n);

    // Now we work with methods!
    stuff = std::bind(&MyStuff::printGoodbye, &goodClass, _1);
    stuff(n);
}

Sorry to the OP ;p Though if you do still need help just let us know with a more detailed post what you are having trouble with exactly.

[JLBorges]

> Is there benefits to using a function pointer over std::function? Or the other way around?

http://www.drdobbs.com/generalized-function-pointers/184403746 (Slightly dated)

[ishti alam]

Thanks...but i think i should learn more about this topic. Then i will tell you details about this problem.