What is difference between uninitialized pointer and null pointer?

Answer:

An uninitialized pointer is a pointer which points unknown memory location while null pointer is pointer which points a null value or base address of segment. 

For example:

int *p;   //Uninitialized pointer

int *q= (int *)0;  //Null pointer

#include<stdio.h>

int *r=NULL;   //Null pointer

What will be output of following c program?

#include<string.h>

#include<stdio.h>

void main(){

    char *p;  //Uninitialized pointer

    char *q=NULL;   //Null pointer;

    strcpy(p,"cquestionbank");

    strcpy(q,"cquestionbank");

    clrscr();

    printf("%s  %s",p,q);

    getch();

}

Output: cquestionbank  (null)