Printing doubles in hexadecimal format

The a and A type specifiers print floating-point numbers such that the coefficient is in hexadecimal format and the exponent is a power of 2, as follows:

printf( " %%a[%a] hexadecimal version of double, exponent=2^p\n",
        aDouble );
printf( " %%A[%A] HEXADECIMAL version of double, exponent=2^P\n\n",
       aDouble );

These type conversions are a recent addition to C and were added for the internal validation of floating-point values. If you ever find yourself in need of these types of conversion, please email me; I would love to know the circumstance for their use.