Pointers

[jabeh]

What's exactly the use of pointers in coding?

[deleted account xyzzy]

https://stackoverflow.com/questions/162941/why-use-pointers

[jonnin]

jabeh (2)
What's exactly the use of pointers in coding?

in 'coding' ... some languages hide pointers entirely from the coder. Some languages rely on them as a key feature. C++ splits the difference.. you can do a lot without a single pointer at all. So the answer depends a lot on the language, but from a c++ perspective the above link is good info.

A short list of things you can do with them in c++ include:
polymorphism
serialization
chained datastructures (graphs, nonbinary trees, ...)
parameter passing (there are a couple of one-off scenarios where doing it any other way is convoluted)

there are also the C uses of pointers that C++ inherits, which can be used to build low level tools. It is unusual to need to do this, but it is supported.

[jabeh]

Thanks joinni, by the way can you provide any code example using pointers, especially the short list you provide. can you give me some code please.

[jonnin]

if you have a struct, you can cast its address to char* to write to a file (serialization)
somefile.write((char*)&somestruct, sizeof(somestruct_type));

a non-binary tree:
struct node
{
int data;
node* children[10]; //can be a vector but its still going to be a vector of pointers.
};

polymorphism... if you read far enough it will start using pointers to base classes and such.
https://www.geeksforgeeks.org/polymorphism-in-c/

as a parameter to a function:
double d[1000];
for(double &z:d) z = something;
...
memset(&d[42], 0, sizeof(double)*1000); //the first parameter is a pointer...

[ne555]

pointers are used to point.
it's the way to define relationships between objects beside composition and inheritance.

class school_bus{
   std::vector<child *> passengers; // a school bus transports children
public:
   void aboard(child *c){
     passengers.push_back(c);
   }
   void crash(){
     for(auto c: passengers)
       c->die();
   }
};

[Duthomhas]

https://youtu.be/yGYqCiAXvrU?t=11s