void toOctal(int num){

 int i, temp, temp2, q, ar[100], count=0, h;

 for (i=0;num>0;i++){
  q=num;
  num=num/8;
  temp=num;
  temp2=temp*8;
  temp=q-temp2;

  count++;
  ar[i]=temp;
 }
 
 for(h=0;h<count;h++){
 printf("%d", ar[count-1-h]);
 }
}

int toDecimal(char *num){

int  b, k, m, n;
  int  len, sum = 0;
 
  len = strlen(num) - 1;
  for(k = 0; k <= len; k++) 
  {
    n = (num[k] - '0');
    if ((n > 8) || (n < 0)) 
    {
      printf("\n\n ERROR! Octal has only 0 to 7!\n");
      return (0);
    }
    for(b = 1, m = len; m > k; m--) 
    {
     b *= 8;
    } 
    sum = sum + n * b;
  }
  return(sum);
}