Is the following code OK?

[vb@gmail.com]

hi all,
I have to compare an address of structure with an absolute address(this
address signifies the start of a memory component).
Now my question is the follwong code leagal:-

#include <stdio.h>

int main()
{
struct t{
int a;
int b;
}temp;

struct t* ptr=&temp;

if(ptr<0x120000 )
printf("What\n" );
else
printf("The hell\n");
return 0;
}

My concern is the comparision in the if statement because a structure
pointer and an unsigned int are being compared. Can there be an
undefined behaviour in any cases ?