Write a C function ftoa() that converts a given floating point number to string. Use of standard library functions for direct conversion is not allowed. The following is prototype of ftoa().
ftoa(n, res, afterpoint) n --> Input Number res --> Array where output string to be stored afterpoint --> Number of digits to be considered after point. For example ftoa(1.555, str, 2) should store "1.55" in res and ftoa(1.555, str, 0) should store "1" in res.
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A simple way is to use sprintf(), but use of standard library functions for direct conversion is not allowed.
The idea is to separate integral and fractional parts and convert them to strings separately. Following are the detailed steps.
1) Extract integer part from floating point.
2) First convert integer part to string.
3) Extract fraction part by exacted integer part from n.
4) If d is non-zero, then do following.
….a) Convert fraction part to integer by multiplying it with pow(10, d)
….b) Convert the integer value to string and append to the result.
Following is C implementation of the above approach.