How to add to String Array from inside recursive function in C -

i trying write c function give me binary representation of number n. function have prints number correctly; string array word updated same data being printed:

#include <stdio.h> #include <stdlib.h>  #define maxbin 100  void printbitsrec(unsigned n, int n_bits, char *w) {     if (n_bits-- > 0) {         printbitsrec(n >> 1, n_bits, w);         if (n & 1) {             printf("1");             *w++ = '1';         }         else {             printf("0");             *w++ = '0';         }      } }  void printbits(unsigned n, int n_bits, int ret) {     char word[maxbin];     printbitsrec(n, n_bits, &word[0]);     word[n_bits + 1] = '\0';     if (ret)         printf("\n");     printf("word = %s\n", word); }  int main() {     printbits(2, 4, 1); } 

is there more elegant way this? doing wrong in code?

here's attempt:

#include <stdio.h> #include <stdlib.h>  #define maxbin 100  char * printbitsrec(unsigned n, int n_bits, char *w) {     if (n_bits-- > 0) {         w = printbitsrec(n >> 1, n_bits, w);         const char c = (n & 1) ? '1' : '0';         putchar(c);         *w++ = c;     }     return w; }  void printbits(unsigned n, int n_bits, int ret) {     char word[maxbin];     char * w = printbitsrec(n, n_bits, &word[0]);     *w++ = '\0';     if (ret)         printf("\n");     printf("word = %s\n", word); }  int main(void) {     printbits(2, 4, 1);     return 0; } 

notable changes:

• use returned value keep track of end of string
• only compute new character once
• use putchar rather printf(), basic performance consideration (printf() overkill when printing single characters)

note no attempt prevent buffer overflow done, of course added.