Adding and Printing elements of an array in C

 Adding and Printing elements of an array in C

The problem seems to be here:

  for (int i=0; i<200; i++){
      fscanf(CFG, "%c", &stringCFG[i]);
      howManyItems++;
      fprintf(output,"%c", stringCFG[i]);
  }

This loop always executes 200 times regardless of what is in the file. In other words - the value of howManyItems will be 200 when the loop is done.

You can check that simply by printing howManyItems after the loop, i.e.

printf("After loop, howManyItems=%d\n", howManyItems);

Since you have:

char stringCFG[200];

then

stringCFG[howManyItems]= ',';  // bad.. writing to stringCFG[200]
howManyItems++;
stringCFG[howManyItems]= '0';  // bad.. writing to stringCFG[201]
howManyItems++;
...

will write outside of the array. That is undefined behavior.

You need to stop the first loop once the whole file has been read. Something like:

  for (int i=0; i<200; i++){
      if (fscanf(CFG, "%c", &stringCFG[i]) != 1)
      {
          // No more data
          break;
      }
      howManyItems++;
      fprintf(output,"%c", stringCFG[i]);
  }

and all the following loops must then use howManyItems as the upper limit.

Like

  for(int i=0; i<howManyItems; i++){
    if(stringCFG[i] == '>'){
      RHS= 1;
    }
    ...
  }

BTW: Since you want to be able to add 4 extra chars, you probably should do:

char stringCFG[200]; --> char stringCFG[200 + 4];

BTW: Hard-coding the value 200 over and over again is bad practice. Instead use a define like:

#define MAX_CHARS 200

and replace all the hard-coded 200 with MAX_CHARS. Then you can adjust the maximum simply by editing one line instead of multiple lines.