C++: Converting Hexadecimal to Decimal

I'm looking for a way to convert hex^{(hexadecimal)} to dec^(decimal) easily. I found an easy way to do this like :

int k = 0x265;
cout << k << endl;

But with that I can't input 265. Is there anyway for it to work like that:

Input: 265

Output: 613

Is there anyway to do that ?

Note: I've tried:

int k = 0x, b;
cin >> b;
cout << k + b << endl;

and it doesn't work.