Sample Programs and Singleton Design Pattern

# include<iostream>
# include<stdio.h>
using namespace std;

class TInstanceCount
{
static int _instanceCount;
public:
TInstanceCount(void)
{
++TInstanceCount::_instanceCount;
}
static int GetInstanceCount(void)
{
return TInstanceCount::_instanceCount;
}
};
int TInstanceCount::_instanceCount=0;

int main(void)
{
TInstanceCount ob1,ob2,ob3,ob4;
int a =ob1.GetInstanceCount();
printf("%d\n",a);
return 0;
}

# include<stdio.h>

# include<iostream>

using namespace std;

class TSingleton

{

private:

int _num1;

int _num2;

private:

TSingleton(const int num1,const int num2):_num1(num1),_num2(num2)

{};

public:

static TSingleton& getInstance(const int num1,const int num2)

{

static TSingleton singletonInstance(num1,num2);

return singletonInstance;

}

void PrintRecord(void)

{

cout<<"Num1 : "<<this->_num1<<endl;

cout<<"Num2 : "<<this->_num2<<endl;

}

};

int main(void)

{

TSingleton& s1=TSingleton::getInstance(500,600);

s1.PrintRecord();

TSingleton& s2=TSingleton::getInstance(100,200);

s2.PrintRecord();

return 0;

}

# include<iostream>

# include<stdio.h>

using namespace std;

class TSingleton

{

int _num1;

int _num2;

static TSingleton* _ptr;

private:

TSingleton(const int num1,const int num2):_num1(num1),_num2(num2)

{ }

public:

static TSingleton* getInstance(const int num1,const int num2)

{

if(TSingleton::_ptr==NULL)

{

TSingleton::_ptr=new TSingleton(num1,num2);

return TSingleton::_ptr;

}

}

void printRecord(void)

{

cout<<"NUm1 : "<<this->_num1<<endl;

cout<<"Num2 : "<<this->_num2<<endl;

}

static void clear(void)

{

if(TSingleton::_ptr!=NULL)

delete TSingleton::_ptr;

TSingleton::_ptr=NULL;

}

};

TSingleton* TSingleton::_ptr=NULL;

int main(void)

{

TSingleton* ptr1=TSingleton::getInstance(100,200);

TSingleton* ptr2=TSingleton::getInstance(500,600);

ptr1->printRecord();

ptr2->printRecord();

TSingleton::clear();

return 0;

}

# include<stdio.h>

# include<iostream>

using namespace std;

int sum(int num1,int num2)

{

return num1+num2;

}

int sub(int num1,int num2)

{

return num1-num2;

}

int menu_list(void)

{

int choice;

cout<<"0.Exit"<<endl;

cout<<"1.Sum"<<endl;

cout<<"2.Sub"<<endl;

cout<<"Enter Choice: ";

cin>>choice;

return choice;

}

void accept_record(int & number)

{

cout<<"Enter Number : ";

cin>>number;

}

void print_record(const int& result)

{

cout<<"Result :"<<result<<endl;

}

int main(void)

{

int choice;

int num1,num2;

while((choice=::menu_list())!=0)

{

int(*ptr)(int,int)=NULL;

int result=0;

switch(choice)

{

case 1:

ptr=&sum;

break;

case 2:

ptr=&sub;

break;

}

if(ptr!=NULL)

{

::accept_record(num1);

::accept_record(num2);

result=ptr(num1,num2);

::print_record(result);

}

}

return 0;

}