#include<iostream>

using namespace std;

struct complex {

 double real;

 double imaginary;

};

int add(int a, int b)

{

 return a + b;

}

double add(double a, double b)

{

 return a / b;

}

complex add(complex a, complex b)

{

 complex s;

 s.imaginary = a.imaginary + b.imaginary;

 s.real = a.real + b.real;

 return s;

}

int main()

{

 complex a = { 2.3,3.2 };

 complex b = { 4.5,5.4 };

 complex c = add(a, b);

 cout << "1+2=" << add(1, 2) << endl;

 cout << "2.2/1.1=" << add(2.2, 1.1) << endl;

 cout << "complex ab=" << c.real << "," << c.imaginary << endl;

 system("pause");

 return 0;

}

 #include<iostream>

using namespace std;

template<class X>

X Quicksort(X a[], int low, int high)

{

 if (low >= high)

 {

  return 0;

 }

 int x = low;

 int y = high;

 int key = a[x];

 while (x < y)

 {

  while (a[y] >= key && x < y)

  {

   --y;

  }

  a[x] = a[y];

  while (a[x] <= key && x < y)

  {

   ++x;

  }

  a[y] = a[x];

 }

 a[x] = key;

 Quicksort(a, low, x - 1);

 Quicksort(a, x + 1, high);

}

int main()

{

 int i, a[5] = { 1,6,2,9,5 };

 Quicksort(a, 0, 5);

 for (i = 1; i < 6; i++)

  cout << a[i] << " ";

 system("pause");

 return 0;

}

#include <iostream>

#include <string>

using namespace std;

class User {

public:

 void setinfo(string name1 = "", string passwd1 = "12345", string email1 = "");

 void changepasswd();

 void printinfo();

private:

 string name;

 string passwd;

 string email;

};

void User::setinfo(string name1, string passwd1, string email1) {

 name = name1;

 passwd = passwd1;

 email = email1;

}

void User::changepasswd() {

 string old;

 int i = 0;

 do {

  cout << "请输入原密码:";

  cin >> old;

  if (old == passwd)

  {

   cout << "请输入修改后的密码:";

   cin >> passwd;

   cout << "修改成功!";

   break;

  }

  else    i++;

  if (i == 3)

   cout << "连续三次输错，请稍后重试！";

 } while (i != 3);

}

void User::printinfo() {

 cout << "name: " << name << endl;

 cout << "password:******" << endl;

 cout << "email: " << email << endl;

}

int main() {

 cout << "testing 1......" << endl;

 User user1;

 user1.setinfo("Leonard");

 user1.printinfo();

 user1.changepasswd();

 user1.printinfo();

 cout << "testing 2......" << endl;

 User user2;

 user2.setinfo("Jonny", "92197", "xyz@hotmail.com");

 user2.printinfo();

 system("pause");

 return 0;

}