Error while tokenizing strings from a string

I want to generate a symbol table from a SIC Assembly code. For that I have tried to separate every strings form the assembly code. Hence while attempting first step for that, I tried this code.

Here, What I have tried is to read the assembly code form a file line by line. And then to separate the strings in the line to tokens.

When I remove the token separation section (as mentioned in the code) I am getting all lines printed as expected. But If I run along with token separation, the first line is getting read and the tokens are separated as I expected. But for the second line I am getting error as segmentation fault. I couldn't trace where I went wrong.

So, I need explanations form experts.

Thanks in advance.

 FILE* sourceCode =  fopen("/home/muthu/LangFiles/SIC/PASS1/PROGRAM.txt","r");
  if(checkForFileOpeningErrors() == ERROR)  //Iam using separate function
      return EXIT_FAILURE;  //Terminate the program.
  int maxLineLength = 50;
  while(1)
  {
           char* lineReader = NULL;  // since getline will reallocate.
       if( getline(&lineReader,(size_t*)&maxLineLength,sourceCode) == -1 )
           break;
       printf("%s",lineReader);

// TOKEN SEPARATION STARTS HERE....   If I comment this section out iam getting all lines printed 
            char* wordReader;
      wordReader = strtok(lineReader," \n");
     开发者_如何学Python printf("%s\n",wordReader);
      while(1)
      {
           wordReader = strtok(NULL," \n");
           printf("%s\n",wordReader);
      }
// TOKEN SEPARATION ENDS HERE....
  }

My FILE:

COPY START 1000  
FIRST STL RETADR 
CLOOP JSUB RDREC  
LDA LENGTH
COMP ZERO
JEQ ENDFIL
JSUB WRREC 
J CLOOP
.
.
.
END

My Sample output:

muthu@muthu-G31M-ES2L:~/LangFiles/PASS1$ ./a.out
All Files successfully opened!! Operation has begun...
COPY START 1000 

COPY
START
1000
segmentation Fault.

When do you expect this loop to terminate?

  while(1)
  {
       wordReader = strtok(NULL," \n");
       printf("%s\n",wordReader);
  }

Uh, you're using strtok() wrong. It will return NULL when no more tokens are found, and you shouldn't try to print that. Also, your loop is never-ending, which will be a problem.

The loop should probably look something like this, since as-is now, you pass the same argument to strtok() on every iteration, which will of course never succeed:

for(wordReader = strtok(lineReader, " \n");
    wordReader != NULL;
    wordReader = strtok(NULL, " \n"))
{
   printf("found token: '%s'\n", wordReader);
}

You never break out of the while(1) loop, so it tries to go on forever, but causes a segmentation fault when strtok returns NULL.

You need to check whether strtok returns NULL, and break out of the loop at that point.