CPP_note

http://www.cplusplus.com/doc/tutorial
1. cin and strings
#include <iostream>
#include <string>
using namespace std;

int main ()
{
  string mystr;
  cout << "What's your name? ";
  getline (cin, mystr);
  cout << "Hello " << mystr << ".\n";
  return 0;
}

2. stringstream
string mystr ("1204");
int myint;
stringstream(mystr) >> myint;

3. passed by reference
#include <iostream>
using namespace std;

void duplicate (int& a, int& b, int& c)
{
  a*=2;
  b*=2;
  c*=2;
}

int main ()
{
  int x=1, y=3, z=7;
  duplicate (x, y, z);
  cout << "x=" << x << ", y=" << y << ", z=" << z;
  return 0;
}
By qualifying them as const, the function is forbidden to modify the values of neither a nor b, but can actually
access their values as references:
string concatenate (const string& a, const string& b)
{
  return a+b;
}

4. function template (are_equal(10,10.0) Is equivalent to: are_equal<int,double>(10,10.0))
#include <iostream>
using namespace std;

template <class T, class U>
bool are_equal (T a, U b)
{
  return (a==b);
}

int main ()
{
  if (are_equal(10,10.0))
    cout << "x and y are equal\n";
  else
    cout << "x and y are not equal\n";
  return 0;
}

5. pointer
#include <iostream>
using namespace std;

int main ()
{
  int firstvalue, secondvalue;
  int * mypointer;

  mypointer = &firstvalue;
  *mypointer = 10;
  mypointer = &secondvalue;
  *mypointer = 20;
  cout << "firstvalue is " << firstvalue << '\n';
  cout << "secondvalue is " << secondvalue << '\n';
  return 0;
}

The arrow operator (->) is a dereference operator that is used exclusively with pointers to objects that have members.
movies_t * pmovie;
pmovie->title is, for all purposes, equivalent to: (*pmovie).title

6.
Classes are an expanded concept of data structures: like data structures, they can contain data members,
but they can also contain functions as members.
empty parentheses cannot be used to call the default constructor:
Rectangle rectb;   // ok, default constructor called
Rectangle rectc(); // oops, default constructor NOT called