static variable in c 2b 2b

1/*
2this example show where and how
3static variables are used
4*/
5
6#include <iostream>
7#include <string>
8
9//doing "using namespace std" is generally a bad practice, this is an exception
10using namespace std;
11
12class Player
13{
14  int health = 200;
15  string name = "Name";
16  
17  //static keyword
18   static int count = 0;
19public:
20  //constructor
21  Player(string set_name)
22    :name{set_name}
23  {
24    count++;
25  }
26  
27  //destructor
28  ~Player()
29  {
30    count--;
31  }
32  
33  int how_many_player_are_there()
34  {
35    return count;
36  }
37  
38};
39
40int main()
41{
42  Player* a = new Player("some name");
43  cout << "Player count: " << *a.how_many_player_are_there() << std::endl;
44  
45  Player* b = new Player("some name");
46  cout << "Player count: " << *a.how_many_player_are_there() << std::endl;
47  
48  delete a;
49  
50  cout << "Player count: " << *b.how_many_player_are_there() << std::endl;
51}
52
53/*output:
541
552
561
57*/

1#include<iostream>
2//Singleton class is a class having only one instance
3class SingleTon {
4
5public:
6	static SingleTon& Get() {
7		static SingleTon s_Instance;
8		return s_Instance;
9	}//there is only one instance of static functions and variables across all instances of class
10	void Hellow() {}
11};
12void Increment() {
13	int i = 0;//The life time of variable is limited to the function scope
14	i++;
15	std::cout << i << std::endl;
16};//This will increment i to one and when it will reach the end bracket the lifetime of var will get  destroyed
17void IncrementStaticVar() {
18	static int i = 0;//The life time of this var is = to program
19	i++;
20	std::cout << i << std::endl;
21}//This will increment i till the program ends
22int main() {
23	
24	Increment();//output 1
25	Increment();//output 1
26	Increment();//output 1
27	IncrementStaticVar();// output 2
28	IncrementStaticVar();// output 3
29	IncrementStaticVar();// output 4
30	IncrementStaticVar();// output 5
31	SingleTon::Get();
32	std::cin.get();
33
34}