#include <cassert>
#include <exception>
#include <iostream>

#include "../include/safe_integer.hpp"

int main(int argc, const char * argv[]){
    std::cout << "example 3:";
    std::cout << "undetected underflow in data type" << std::endl;
    std::cout << "Not using safe numerics" << std::endl;
    // problem: decrement can yield incorrect result
    try{
        unsigned int x = 0;
        // the following silently produces an incorrect result
        --x;
        std::cout << x << " != " << -1 << std::endl;

        // when comparing int and unsigned int, C++ converts
        // the int to unsigned int so the following assertion
        // fails to detect the above error!
        assert(x == -1);

        std::cout << "error NOT detected!" << std::endl;
    }
    catch(std::exception){
        // never arrive here
        std::cout << "error detected!" << std::endl;
    }
    // solution: replace unsigned int with safe<unsigned int>
    std::cout << "Using safe numerics" << std::endl;
    try{
        using namespace boost::numeric;
        safe<unsigned int> x = 0;
        // decrement unsigned to less than zero throws exception
        --x;
        assert(false); // never arrive here
    }
    catch(std::exception & e){
        std::cout << e.what() << std::endl;
        std::cout << "error detected!" << std::endl;
    }
    return 0;
}