char* itoa(int val, char *s, int radix)
The function itoa() converts the integer value from val into an ASCII representation that will be stored under s. The caller is responsible for providing sufficient storage in s.
The minimal size of the buffer s depends on the choice of radix. For example, if the radix is 2 (binary), you need to supply a buffer with a minimal length of 8 * sizeof (int) + 1 characters, i.e. one character for each bit plus one for the string terminator. Using a larger radix will require a smaller minimal buffer size.
If the buffer is too small, you risk a buffer overflow.
radix as base, which may be a number between 2 (binary conversion) and up to 36. If radix is greater than 10, the next digit after '9' will be the letter 'a'.If radix is 10 and val is negative, a minus sign will be prepended.
The itoa() function returns the pointer passed as s.