#include <stdio.h>

//reverse a string in place
void strrev(char* str)
{
  int len = 0;
  for(len=0; str[len]; len++);
  int i;
  for(i=0; i&lt;len/2; i++) {
    char tmp = str[i];
    str[i] = str[len-i-1];
    str[len-i-1] = tmp;
  }
}

void my_itoa(int num, char* buf, int base)
{
  int i = 0;
  while(num != 0)
  {
    int r = num % base;
    num -= r;
    num /= base;
    char c = r + 48; //convert the digit to char
    buf[i] = c;
    i++;
  }
  buf[i] = 0;
  strrev(buf);
}

int main(int argc, char** argv)
{
  char a[50] = "hello world this";
  char b[50] = "stuff in the water";
  strrev(a);
  strrev(b);
  printf("%s\n%s\n", a, b);
  char c[100];
  my_itoa(12, c, 5);
  printf("%s\n", c);

  return 0;
}