Thread: Eliminating extra spaces between words

Hi all, I'm quite new to C programming, so forgive me if I've made silly mistakes. I'm tryin to write a program to remove the extra spaces between words.

For example:

Code:

Input: C Programming        is    fun. 
Output: C Programming is fun.

So far, I'm only able to remove all spaces, and I had a problem with the output of my program. The program would print funny characters at the end of the output. I would greatly appreciate if anyone could point out to me what is wrong, and how I could further implement my code to meet my objectives. (like the above example). Thank you!

Code:

   char input[50];
   char output[50];
   int i=0, j=0;

   printf("Input = ");
   fgets(input, 50, stdin);
  
   while(input[i]!='\0')
   {
      if(isspace(input[i]))
         i++; 
      else if(!isspace(input[i]) && input[i]!='\0')
      {
	      output[j] = input[i];
	      i++;
	      j++;
      }
   }
   
   puts(output);

When I run my program, I get

Code:

Input = there     is   a
Output = thereisa(funny characters here)

Yeap thx! I know that i need to check for more than 1 space in a row, but how do I implement it? I've been trying, but seem not to be able to code it without getting any errors.

or like this

Code:

do
   {
      if(isspace(input[i]) && isspace(input[i+1]))
         i++; 
      else 
      {
          output[j] = input[i];
          i++;
          j++;
      }
   }while(input[i-1]);

Thanks a lot Quantum1024! It works perfectly. Could I know why the alogorithm is done in that manner? I'm a bit confused about having a do while loop there. Thanks a lot cos I wanna learn more. =)

or like this, using pointers..

Code:

   char *pi = input;
   char *po = output;

   do
   {
      if(isspace(*pi) && isspace(*(pi+1)))
         pi++; 
      else 
          *(po++) = *(pi++);
   }while(*(pi-1));

The logic isn't correct if you aren't on an ASCII encoded machine.