#include <iostream>

using std::cout, std::cin, std::endl;

const char *hf1_function_pointer(const char *s)

{

cout << s << endl;

return "world";

}

void function_pointer()

{

cout << endl

<< "test function_pointer" << endl;

const char *(*hf1)(const char *);

hf1 = hf1_function_pointer;

cout << hf1("hello") << endl;

}

void variable_reference()

{

cout << endl

<< "test variable_reference" << endl;

int n = 3;

int &r = n;

r = 5;

cout << "set r=5:: n: " << n << "; r: " << r << endl;

n = 7;

cout << "set n=7:: n: " << n << "; r: " << r << endl;

}

void hf1_swap_variable(int &a, int &b)

{

int tmp1;

tmp1 = a;

a = b;

b = tmp1;

}

void swap_variable()

{

cout << endl

<< "test swap_variable" << endl;

int a = 3;

int b = 5;

cout << "before swap:: a: " << a << "; b: " << b << endl;

hf1_swap_variable(a, b);

cout << "after swap:: a: " << a << "; b: " << b << endl;

}

void const_pointer()

{

cout << endl

<< "test const_pointer" << endl;

int a = 3;

int b = 5;

const int *p = &a;

cout << "*p=&a:: " << *p << endl;

p = &b;

cout << "*p=&b:: " << *p << endl;

}

void constant_variable()

{

const int MAX_VAL = 32;

const double PI = 3.14;

const char *SCHOOL_NAME = "Peking University";

}

void new_variable()

{

cout << endl

<< "test new_variable" << endl;

int *z1 = new int;

*z1 = 3;

cout << "*z1=3: " << *z1 << endl;

delete z1;

z1 = new int[2];

z1[0] = 1;

cout << "new int[4]: "

<< z1[0] << " "

<< z1[1] << " "

<< endl;

delete[] z1;

}

int hf1_overload(int a, int b)

{

cout << "hf1_overload(int, int): ";

if (a > b)

return a;

return b;

}

double hf1_overload(double a, double b)

{

cout << "hf1_overload(double, double): ";

if (a > b)

return a;

return b;

}

void function_overload()

{

cout << endl

<< "test function_overload" << endl;

cout << hf1_overload(3, 4) << endl;

cout << hf1_overload(3.0, 4.0) << endl;

}

int hf1_function_default_argument(int x1, int x2=0, int x3=0)

{

return x1 + x2 + x3;

}

void function_default_argument()

{

cout << endl

<< "test function_default_argument" << endl;

cout << "hf1(1): " << hf1_function_default_argument(1) << endl;

cout << "hf1(1,2): " << hf1_function_default_argument(1,2) << endl;

cout << "hf1(1,2,3): " << hf1_function_default_argument(1,2,3) << endl;

}

int main(int argc, char *argv[])

{

cout << "test argc / argv" << endl;

cout << "argc: " << argc << endl;

for (int i = 0; i < argc; i++)

cout << "argv: " << argv[i] << endl;

function_pointer();

variable_reference();

swap_variable();

const_pointer();

new_variable();

function_overload();

function_default_argument();

return 0;

}