Structs

Structs combine multiple variables into one
Structs are user-defined datatypes

defining the data type:
struct person {
  string firstname;
  string lastname;
  char middleinitial;
  long int ssn;
};

generic:
struct typename { variabledefinitions };


using the datatype

person max; // just like any other datatype

max.firstname = "Max";  // access members with a dot (.)
max.middleinitial = '-';

// initialization: has to be in the same order!
person john = {"John","Lastname",'X',123456}; 

Partial initialization of structs is possible!
person johnp = {"John","Lastname",'X'};
(Works the same as in arrays, everything not initialized gets set to 0)

Assignment of structs is possible:
max = john;  // overwrites every member of max with the information from john

Pointers to structs

person* pointermax;       // declare a pointer to a struct
pointermax = new person; // allocate space

// normally do either:
(*pointermax).firstname = "Max"; // assign one element
pointermax->lastname = "Berger"; // special notation for pointers to structs

// or:
(*pointermax) = max; // assign the whole thing
// end either / or

delete pointermax; // free memory



Complete example:
#include <iostream>
#include <string>
using namespace std;

struct person
{
  string lastname;
  string firstname;
  long ssn;
};

person readInAPerson()
{
  person p;
  cout << "Enter the first name: "; cin >> p.firstname;
  cout << "Enter the last name:  "; cin >> p.lastname;
  cout << "Enter the SSN:        "; cin >> p.ssn;
  return p;
}

void printAPerson(person toPrint)
{
  cout << toPrint.firstname << " " << toPrint.lastname << ": " << toPrint.ssn;
  cout << endl;
}


int main()
{
  cout << "Enter person 1" << endl;
  person p1;
  p1 = readInAPerson();
  cout << "Enter another person:" << endl;
  person p2;
  p2 = readInAPerson();
  printAPerson(p1);
  printAPerson(p2);
  return 0;
}