Dev - C++ - programa que lea 2 caracteres y despliegue su valor em decimal

#include <iostream>

#include <cctype>

using namespace std;

int main(){

    char a[3];

    cout << "Numero de dos cifras: ";

    cin >> a;

    if( isdigit( a[0] ) && isdigit( a[1] ) )

        cout << "\nNumero decimal: " << a << endl;

    else if( ( isdigit( a[0] ) ||

           ( int(a[0]) >= 65 && int(a[0]) <= 70 ) ||

           ( int(a[0]) >= 97 && int(a[0]) <= 102 ) ) &&

           ( isdigit( a[0] ) ||

           ( int(a[0]) >= 65 && int(a[0]) <= 70 ) ||

           ( int(a[0]) >= 97 && int(a[0]) <= 102 ) ) )

           cout << "\nNumero Hexadecimal: " << a << endl;

    else cout << "\nNumero erroneo" << endl;

    return 0;

}

else if( ( isdigit( a[0] ) ||

           ( int(a[0]) >= 65 && int(a[0]) <= 70 ) ||

           ( int(a[0]) >= 97 && int(a[0]) <= 102 ) ) &&

           ( isdigit( a[1] ) ||

           ( int(a[1]) >= 65 && int(a[1]) <= 70 ) ||

           ( int(a[1]) >= 97 && int(a[1]) <= 102 ) ) )