/*
Overview: 
1. not survey of languages but different types of languages
2. not about syntax (might as well be about fonts)
3. It is about what's important in languages versus what's superficial
 */


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

void f1(int x, int y)  // "call by value"
{
  int z = x;
  x = y;
  y = z;
}

void f2(int* x, int* y)   // "call by value" but value type is pointer
{
  int *z = x;
  x = y;
  y=z;
  /* 
  int z = *x;
  *x = *y;
  *y = z;
   */
}

void f3(int& x, int& y) // "call by reference"
{
  int z = x;
  x = y;
  y = z;
}

int f(int x)
{
  cout << "in f, returning 0" << endl;
  return 0;
}
int g(int x)
{
    cout << "in g, returning " << x*x << endl;
    return x*x;
}


class account
{
private:
  string name;
  string password;
  double balance;
public:
  account(string n, double init)
  {
    name = n;
    balance = init;
    password = "xyzzy";
  }
  void withdraw(double amt)
  {
    string pw;
    cout << "Enter password: "; cin >> pw;
    if (pw==password && amt>0 && amt<balance) balance-=amt;
  }
  void info()
  { cout << name << " has a balance of " << balance << endl; }
};

class unlocked
{
public:
  string name;
  string password;
  double balance;
};


int main()
{
  int x = 1, y = 2;
  f1(x,y);
  cout << x << " and " << y << endl;
  f2(&x,&y);
  cout << x << " and " << y << endl;
  f3(x,y);
  cout << x << " and " << y << endl;

  f(g(2)); // which function gets called first?

  x = 2;
  //cout << 1/(x-2); // runtime versus compiler error, halting problem
  cout << 0 * 1/(x-2); // what will this do? what should it do? (benchmark)

  cout << "\n-----------------\n";
  account youraccount("hacker geek",1000);
  youraccount.withdraw(400);
  youraccount.info();

  unlocked *youracc = (unlocked*)&youraccount;
  cout << " your private password is " << youracc->password << endl;
  youracc->balance = -50000;
  youraccount.info();
  
  return 0;
}