struct & union difficulty. getting segmentation fault error.

[koopey]

I am getting segmentation fault error while debugging. while running normally, nothing is displayed including no error.

  #include <iostream>
#include <cstring>
using namespace std;

union u1
{
	struct trinode* arrayptr[26];
	char* chararrayptr;
};

typedef
struct trinode
{
	int tag;
	union u1 option;
	char* asitis;
}* trptr;

int main()
{
	char word[20];
	trinode* root;
	root->tag=1;
	for(int i=0;i<26;i++)
	root->option.arrayptr[i]=NULL;
	root->asitis=NULL;
	cout<<"Enter the word: ";
	cin>>word;

}

[SakurasouBusters]

You are accessing an uninitialized pointer variable. Of course this is what we call "access violation".

trinode* root; // Not initialized
root->tag = 1; // The problem