C++ : Static Member 2

Example:1
Give output of the following program

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

class sample
{
private:
     static int a;
public:
     void disp();
};
int sample::a;      //1
//int sample::a=100;     //2
void sample::disp()
{
cout<<"a= "<<a<<endl;
}
int main()
{
    /* clrscr(); */
    sample e;
    e.disp();
    getch();
    return(0);
}

Output:

// if statments 1 is active
a= 0
// if statments 2 is active
a= 100

Example:2
Give output of the following program

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

class sample
{
private:
	static int a;
public:
	void disp();
};
int sample::a;	//1
//int sample::a=100;      //2
void sample::disp()
{
    for(int i=0;i<=10;i++)
        a+=i; //a=a+i;
    cout<<"a= "<<a<<endl;
}
int main()
{
    /* clrscr(); */
    sample e;
    e.disp();
    getch();
    return(0);
}

Output:

//if statement 1 is active
a= 55

//if statement 2 is active
a= 155