http://www.cplusplus.com/reference/clibrary/cstdlib/itoa/Portability
This function is not defined in ANSI-C and is not part of C++, but is supported by some compilers.
A standard-compliant alternative for some cases may be sprintf:
sprintf(str,"%d",value) converts to decimal base.
sprintf(str,"%x",value) converts to hexadecimal base.
sprintf(str,"%o",value) converts to octal base.