Sunday, January 1, 2012

What IsDangling Pointer ?

DAnging Pointer :::::::
If any pointer is pointing the memory address of any variable , but after sometime the variable is deleted  while the pointer is still pointing such memory location. Such pointer is known as dangling pointer .



  









e.g :
  

#include<stdio.h>

int *call();
void main(){

int *ptr;
ptr=call();

fflush(stdin);
printf("%d",*ptr);

}
int * call(){

int x=25;
++x;

return &x;
}


Output :::::
 Garbage Value

variable x is local variable. Its scope and lifetime is within the function call hence after returning address of x variable x became dead and pointer is still pointing ptr is still pointing to that location.