vendredi 26 décembre 2014

The difference between *s.pd and s->pd


I was reading about copy constructors for structs and i found this example:



#include <iostream>
#include <string>
using namespace std;

struct SomeData {
int * pd;
string id;
SomeData(SomeData & ref) {
cout << "Copy Constructor called" << endl;
pd = new int (*ref.pd);
id = "Copy Constructed";
}
SomeData(string name) {
pd = new int(0);
id = name;
cout << "Constructor for " << id << endl;
};
~SomeData() {
cout << "Destructor for " << id << endl;
delete pd;
}
};

int main() {
SomeData s("First");
*s.pd = 9;
SomeData s2=s;
cout << *s2.pd << endl;
return 0;
}


in the main, the member pd of SomeData is accessed using the dereference, but why is that, isn't the correct way is



s->pd=9;


why was it written like that in the example?





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