Nested Namespace Declaration

#include <iostream>
using namespace std;

namespace Config {
    namespace ADC { int resolution = 12; }
    namespace PWM { int frequency = 1000; }
}

int main() {
    using namespace Config;
    cout << "ADC.resolution=" << ADC::resolution << "\n";
    cout << "PWM.frequency=" << PWM::frequency << "\n";
    return 0;
}