Binary to hex

#include <iostream>
#include <math.h>
using namespace std;
template <typename X>
inline X abs(const X &a) { return a < 0 ? -a : a; }

int main()
{
    int a; cin >> a;
    cout << "abs: " << abs(a) << endl;
    cout << "int: " << a << endl;
    cout << "binary abs: ";
    for(int i = 7;i>=0;i--)
        cout<< bool(abs(a)&(1<<i));
    cout << endl;
    cout << "binary: ";
    for(int i = 7;i>=0;i--)
        cout<< bool(a&(1<<i));
    cout << endl;
    cout.setf(ios::showbase);
    cout << "hex: " << hex << int(char(a));
}