Pointers

[slx47]

ok i want to make a function and use a pointer and make it in free store part of the memory like this:

#include <iostream.h>

void hi();

int main ()

{
cout<<"hi"<<endl;
hi();
cout<<pAge<<endl;

/* it doesnt remember pAge when it should be in the free store part of memory which means it should stay in memory right ? */

}

void hi()

{
int * pAge = new short int;
*pAge = 6;

}

why is pAge deleted from memory when i put it in free store where it shouldnt be deleted ?

[abdul]

That is because of your function:

void hi() 

{ 
int * pAge = new short int; 
*pAge = 6; 

} 

You are trying to reinitialize the pointer as a new integer inside the function and the function will delete the pointer as soon as it's returned. So you have nothing left in the point after you call the function.

A working approach would be like this:

#include <iostream.h> 

void hi(); 

int main () 

{ 
int * pAge = new short int;  //initialize the pointer outside the function
cout<<"hi"<<endl; 
hi(); 
cout<<pAge<<endl; 

/* it doesnt remember pAge when it should be in the free store part of memory which means it should stay in memory right ? */ 

} 

void hi() 

{ 
//just set the pointer's value
*pAge = 6; 
} 

[slx47]

ok now I see what was wrong. Thanks for the reply.

[CornedBee]

It doesn't free the memory, it just forgets the pointer. You've created a fine memory leak here...

BTW, abdul's code won't work either because the identifier pAge is local to the function main and can't be used in hi.

[parksie]

And note that you should be using the Standard C++ Library headers (i.e. <iostream> not <iostream.h>).


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