How to obtain 100% branch coverage with gcovr with `if / else if / else`

I'm using gcovr for the first time and have hit a confusing issue with this code:

    for (int i = 0; i < 4; i++)
    {
        bool a = i & 1;
        bool b = i & 2;

        if (a && b)
            printf("a and b\n");
        else if (a && !b)
            printf("a not b\n");
        else
            printf("the other two\n");
    }

(The code works as you'd expect, so I'm not going to paste the output.)

However, gcovr decides I don't have full branch coverage:

✓✓     5 for (int i = 0; i < 4; i++)
         {
       4     bool a = i & 1;
       4     bool b = i & 2;

✓✓✓✓  4     if (a && b)
       1        printf("a and b\n");
✓✓✓✗  3      else if (a && !b)
       1         printf("a not b\n");
              else
       2         printf("the other two\n");
          }

Clearly the one of the four permutations is not handled by the else if, but only because it's been handled by the first if.

I'm grumpy because the net result is less than 100% branch coverage. Is this just "the way" or have I fatally misunderstood something?

You may want to refactor:

if (a)
{
    if (b)
    {
        std::cout << "a and b\n";
    }
    else
    {
        std::cout << "a and not b\n";
    }
}
else
{
    std::cout << "not a\n";
}

In your posted code, the a is evaluated in two if statements.
The above example removes the else if condition.