Print a Char as a Number

 When you are interested in the number of bits in your  integer such as in embedded programming, you often find yourself trying to print an 8 bit byte and it appears as the character rather than the number.

uint8_t byValue{65};
std::cout << "Value:" << byValue << std::endl;
// Result
//     Value:A

This occurs because uint8_t acts like a C-style char.

You can overcome this by casting it to a larger integer type:

uint8_t byValue{65};
std::cout << "Value:" << static_cast<uint32_t>(byValue);
// Result
//     Value:65

But that isn't so readable.

Alternatively, you can promote it to an int value by using unary addition, add 0 to keep the same value.

uint8_t byValue{65};
std::cout << "Value:" << byValue + 0 << std::endl;
// Result
//     Value:65 

I find this easier to read.

Iterating through std::maps

 Map Iterators in C++17

I'm not going to comment on whether it is right or wrong to iterate through a map but bear in mind that there are other containers that are faster to iterate through.

This snippet shows the 3 ways I know to iterate through a map and the syntax to use the data. Note that the named pair is only available since C++17.

class MyClass

{

public:

    std::map<int, int> m_map;

    MyClass():

        m_map{}

    {

    }

    void Print(const int a, const int b)

    {

        std::cout << "\ta:" << a << " b:" << b << std::endl;

    }

    void Run()

    {

        m_map[1]=2;

        m_map[2]=4;

        std::cout << "Iterator:\n";

        for (auto it = m_map.begin(); it != m_map.end(); it++)

        {

            Print(it->first, it->second);

        }

        std::cout << "Auto pair:\n";

        for (auto pr : m_map)

        {

            Print(pr.first, pr.second);

        }

        std::cout << "Named pair:\n";

        for (auto& [a,b] : m_map)

        {

            Print(a, b);

        }

    }

    /* prints:

        Iterator:

            a:1 b:2

            a:2 b:4

        Auto pair:

            a:1 b:2

            a:2 b:4

        Named pair:

            a:1 b:2

            a:2 b:4

    */

};

Planning a Day's Coding

 Planning a Day's Coding

There is a lot of advice and are a lot of tools online to plan your work but for short term planning as a busy software engineer, the following works for me.

1. Write down on a piece of A4 all the jobs you think you need/want to do.
2. Assign priorities based on the following:

Priority 1: Add essential functionality.

Priority 2: Add expected functionality.

Priority 3: Same functionality but tidier or improved code.

Priority 4: Documentation.

Priority 5: Optimisation.

Then, obviously work through jobs in priority order.

But also, spend some small amount of time working on something for which there is no allocated time.  This may be a little utility to help you build the code, speed backup, reorganise your desk or updating a blog ;-)

Using Boost Assign to initialise a list of a list.


std::list<std::list<int> > listOfListOfInts = list_of(list_of<int>(1)(2))
                                                     (list_of<int>(1)(2));
assert(listOfListOfInts.front().front() == 1);

Note that the inner lists need to the type hint. Visual Studio 2008 caused a compiler crash without it!

keywords for search: nest nested std stl list boost assign list_of initialise

Note: modern C++ has initialisation built in now.  Use {} for all initialisation.

The application failed to initialize properly 0x0000007b

Thanks Microsoft - what a helpful error message.

My little test application consisted of 3 projects one of which had the /clr switch. I removed that and it ran.

So if you get this error message I suggest you check all settings match.  If you get this error message in someone else's code then you probably have the wrong DLL and I can't help further.