Thread: Should i pass address of pointer or just pointer???

Firstly see the code:

Code:

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

typedef struct temp
{
    int data;
} T;
 

void setframe2( T **tp)
{
    (*tp)->data = 2;
}


void setframe3( T *tp)
{
    tp->data = 3;
}


void setframe( T *tp)
{
    tp->data = 1;
    setframe2(&tp);
    setframe3(tp);
    
} 

 
void main()
{
 
     T  tvar;
     tvar.data=0;

     cout<<"\nValue of data before call to setframe "<<tvar.data;

     setframe(&tvar);

     cout<<"\nValue of data after call to setframe "<<tvar.data;
    
    
getch();
 
}

OUTPUT
Value of data before call to setframe 0
Value of data after  call to setframe 3

In setframe i have T *tp

when calling to setframe2, i am passing its address
setframe2(&tp);
and in setframe2 , tp->data has been changed
and change is permanant as it should be.

but when calling to setframe3, i am passing just pointer , not its address
setframe3(tp);
and in setframe3 , tp->data has been changed
and change is permanant here too , why??

why??
i mean i am not passing address of pointer
so why changes made are permanant, not local .