Convert long integer value to string.
  Converts a long integer value to a null-terminated string using the specified radix and stores the result in the given buffer.
  If radix is 10 and value is negative the string is preceded by the minus sign (-). With any other radix, value is always considered unsigned.
  buffer should be large enough to contain any possible value: (sizeof(long)*8+1) for radix=2.

Parameters.

value

Value to be represented as a string.

buffer

Buffer where to store the resulting string.

radix

Numeral radix in which value has to be represented, between 2 and 36.

Return Value.
  A pointer to the string.

Portability.
  Not defined in ANSI-C. Supported by some compilers.

Example.

/* ltoa example */
#include <stdio.h>
#include <stdlib.h>

main ()
{
  int i;
  char buffer [sizeof(long)*8+1];
  printf ("Enter a number: ");
  scanf ("%d",&i);
  ltoa (i,buffer,10);
  printf ("decimal: %s\n",buffer);
  ltoa (i,buffer,16);
  printf ("hexadecimal: %s\n",buffer);
  ltoa (i,buffer,2);
  printf ("binary: %s\n",buffer);
  return 0;
}

See also.
  atof, atol, ecvt, fcvt, gcvt, itoa, strtod