Remove extra white space from inside a C string?

Question

I have read a few lines of text into an array of C-strings. The lines have an arbitrary number of tab or space-delimited columns, and I am trying to figure out how to remove

Answer 1

The following code modifies the string in place; if you don't want to destroy your original input, you can pass a second buffer to receive the modified string. Should be fairly self-explanatory:

#include 
#include 

char *squeeze(char *str)
{
  int r; /* next character to be read */
  int w; /* next character to be written */

  r=w=0;
  while (str[r])
  {
    if (isspace(str[r]) || iscntrl(str[r]))
    {
      if (w > 0 && !isspace(str[w-1]))
        str[w++] = ' ';
    }
    else
      str[w++] = str[r];
    r++;
  }
  str[w] = 0;
  return str;
}

int main(void)
{
  char test[] = "\t\nThis\nis\ta\b     test.";
  printf("test = %s\n", test);
  printf("squeeze(test) = %s\n", squeeze(test));
  return 0;
}