code for converting float to string

If scanf() is big and slow, check for the availability of atof() or strtod().

If sprintf() is big and slow, check for the availability of ecvt(), fcvt() or gcvt() functions.

The scanf() and sprintf() functions are normally never implemented monolitically. They normally makes use of helper functions like the above suggestions, and they may be used directly.

By the way, don't stop using scanf() because it is large or slow. Stop using it because it is quite lousy. It has a tendancy to be dangerous. It has a tendancy to leave data in the input buffer. It only returns the number of converted arguments - not the location of the first erroneous character. It isn't always obvious how to write the formatting string, to handle non-convertable data in the input string.

If scanf() is big and slow, check for the availability of atof() or strtod().

If sprintf() is big and slow, check for the availability of ecvt(), fcvt() or gcvt() functions.

The scanf() and sprintf() functions are normally never implemented monolitically. They normally makes use of helper functions like the above suggestions, and they may be used directly.

By the way, don't stop using scanf() because it is large or slow. Stop using it because it is quite lousy. It has a tendancy to be dangerous. It has a tendancy to leave data in the input buffer. It only returns the number of converted arguments - not the location of the first erroneous character. It isn't always obvious how to write the formatting string, to handle non-convertable data in the input string.