Replacing tabs in the input

Hey everyone, I am currently working through the K&R book trying to teach myself C and one of the exercises is confusing me. The exercise is this:
Write a program detab that replaces tabs in the input with the proper number of blanks to space to the next tab stop. Assume a fixed set of tab stops, say every n columns. Should n be a variable or a symbolic parameter?

I think I understand what it is asking and have written a program that seems to work. I wrote the program to display the modified tabs rather than changing the string entered itself though I don't think it would be too difficult to switch in any case. Here is the function I wrote:

Code:

void printstring(char string[], int n)
{
  int currentcolumn=1;
  int i, x;
  for(i=0; string[i]!='\0'; i++, currentcolumn++)
    {
      if(string[i]=='\t')
	for(x=0; currentcolumn%n!=0; x++)
	  {
	    putchar(' ');
	    currentcolumn++;
	  }
      else
	putchar(string[i]);
      if(currentcolumn==80 || string[i]=='\n')
	currentcolumn=0;
    }
}

Does anyone have any suggestions on how that could be improved or changed? Or maybe I am missing the point of the exercise entirely . I am very new to C so any suggestions would be greatly appreciated.

Thanks!

Slight issue here:

Code:

int currentcolumn=1

You set it to one first off, then every time through the loop, you do this:

Code:

if(currentcolumn==80 || string[i]=='\n')
	currentcolumn=0

So the first line will be one off.

Quzah.