Essential C++ / Floating point arithmetic

#include <iostream>
#include <string>

int main(int argc, char **argv) {
    double a = 0.1;
    double b = 0.2;
    double c = 0.3;
    if (a + b == c) {
        // This never prints on IEEE754-compliant machines
        std::cout << "This Computer is Magic!" << std::endl; 
    } else {
        std::cout << "This Computer is pretty normal, all things considered." << std::endl;
    }
}