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)

---

You need to check for more than one space in a row and terminate the output string with '\0', that's what's causing the funny characters at the end.

Code:

---

  while(input[i])
  {
      if(isspace(input[i]) && isspace(input[i+1]))
        i++;
      else
      {
          output[j] = input[i];
          i++;
          j++;
      }
  }
  output[j] = '\0'

---

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));

---

i have seen the usage of isspace function.thats nice.
but you can use the ascii value of space instead.the ascii value of space is 10 i suppose.so

Code:

---

while(input[i]!=\0)
{
          if(input[i]==10)
          {
                  count++;
          }
          if(count!=2)
          {
                    output[i]=input[i];
          }
          else if(count[i]==2)
          {
                      continue;
          }
}

---

well may be there might be some syntax errors.but i believe the logic to be correct :rolleyes:

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

Furthermore, we can make it nice and pretty by doing this instead:

Code:

---

    while( *in )
    {
        while( !isspace( ( *out++ = *in++ ) ) );
        while( isspace( *in ) ) in++;   
    }

---

Well, it's fun anyway.

Quzah.