Segmentation fault when passing pointer into function

Question

I am trying to pass a pointer into a function so that I can make use of more functions. I have been using the code below and have been getting segmentation errors whenever I run the program. Where do I need to add pointers to make this work?

I have used things such as FILE** filePointer and &fileName but this still produces a segmentation error.

  FILE* filePointer = fopen(fileName, "r");

  checkIfPointerIsNull(filePointer);

  char output[256];

  printQuestion(output,filePointer);

  actualAnswer1 = getactualAnswerX(6,output,filePointer);
  actualAnswer2 = getactualAnswerX(7,output,filePointer);
  actualAnswer3 = getactualAnswerX(8,output,filePointer);
  actualAnswer4 = getactualAnswerX(9,output,filePointer);

  userAnswer = getUserInput("word");

int printQuestion(output,filePointer)
{
  int i,j;
  j = getRandomNumber()%4;
  for(i=j;fgets(output, sizeof(output), filePointer) != NULL;i++)
  {
    if(i<=5)
    {
      printf("%02d: %c", i, output);
    }
  }
  return 0;
}

char getactualAnswerX(a,output,filePointer)
{
  int i;
  char actualAnswer1,actualAnswer2,actualAnswer3,actualAnswer4;
  for(i=a;fgets(output, sizeof(output), filePointer) != NULL;i++)
  {
    if(i==6)
    {
      fscanf(filePointer, "%c", actualAnswer1); 
      return(actualAnswer1);
    }
    if(i==7)
    {
      fscanf(filePointer, "%c", actualAnswer2);
      return(actualAnswer2);
    }
    if(i==8)
    {
      fscanf(filePointer, "%c", actualAnswer3);
      return(actualAnswer3);
    }
    if(i==9)
    {
      fscanf(filePointer, "%c", actualAnswer4);
      return(actualAnswer4);
    }
  }
  fclose(filePointer);
}

int checkIfPointerIsNull(filePointer)
{
  if(filePointer==NULL)
  {
    printf("Can't load questions");
    return 1;
  }
}

char getUserInput(word)
{
  char userInput;
  printf("Input");
  printf("%c",word);
  scanf("%c",userInput);
  return(userInput);
}

See https://stackoverflow.com/questions/492384/how-to-find-the-sizeof-a-pointer-pointing-to-an-array — Barmar, Nov 08 '19 at 22:52
@barmar it happens in all of the functions in the code above — z5678, Nov 08 '19 at 22:53
You're missing the parameter type declarations on all your function definitions. — Barmar, Nov 08 '19 at 22:56
`output` is a string, the argument corresponding to `%c` must be `char`. — Barmar, Nov 08 '19 at 22:57
I recommend in your case to turn on `-Wall` when compiling, and take a look at the warnings. — HAL9000, Nov 09 '19 at 00:06

0___________ · Accepted Answer · 2019-11-08T23:03:05.200

In scanf you need to pass pointrer to the object you want assign the scanned value

scanf("%c",userInput); -> scanf("%c",&userInput);

And in many other places in your code. And it is the most likely the source of your problems

You need also to declare types of parameters otherwise they are assumed as integers.

Read the warnings as you have for sure uncountable number. You have so many issues here - almost every single line is wrong. So start from the warnings

Segmentation fault when passing pointer into function

1 Answers1