Adapt the ideas printd to write a recursive version of itoa; that is ,convert an integer into a string by calling a recursive routine.

#include <math.h>

/* itoa: convert n to characters in s; recursive    */
void itoa(int n, char s[]){
     static int i;

     if(n /10)
        itoa(n/10 , s);
     else {
           i = 0;
           if (n < 0)
               s[i++] = '-';
     }
    s[i++] = abs(n) % 10 + '0';
    s[i] = '\0';
}