I don't know the cause of this segmentation fault

Hello. For one of my classes, I have to write a program that reads in a file that contains a string and looks for occurrences of substrings asked by the user. I am running this on Ubuntu by the way.

Anyway, the terminal commands are

echo "abcdefgh" > bar
./file bar bc

where file is the name of my program, bar is the file that "abcdefgh" is saved to, and bc is the string the user wants to find. The code for my program is below

Code:

---


#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>


int main(int argc, char *argv[])
{
    FILE *pFile;
    char *textFile=NULL;
    textFile=(char *)malloc(sizeof(char)*10);
    pFile=fopen(argv[1],"r");
   
    int count;
   
    while(fgets(textFile,sizeof(textFile)-1,pFile)!=NULL)
    {


    if(argc>1)
    {
    for(count=1;((textFile=strstr(textFile,argv[count]))!=NULL);count++)
    {
    textFile++;
    }//end for
    }//end if
    }//end while
           
printf("The string appeared: %d times\n",count);


fclose(pFile);


free(textFile);


return 0;


}//end main

---

I am receiving the Segmentation Fault error but have no idea where the problem is or how to fix it. If someone could tell me, that would be great.

Well there are so many places it could go wrong.

> textFile=(char *)malloc(sizeof(char)*10);
You don't check for success here.

> pFile=fopen(argv[1],"r");
You don't check for success here.

> while(fgets(textFile,sizeof(textFile)-1,pFile)!=NULL)
You're lying to fgets about the true size of the buffer. sizeof() in a pointer does NOT tell you how much data it is pointing to.

> for(count=1;((textFile=strstr(textFile,argv[count]))!=NULL);count++)
Your loop pays no attention to argc, so you could be accessing argv out of bounds

> textFile++;
Modifying a pointer to something malloc'ed

> free(textFile);
Freeing a modified pointer.

One more Salem missed, the string that is being read in does not have a null-terminator appended.

So yeah, there's 7 reasons why it would segfault all up so far. That's pretty impressive for a mere 41 lines of code.

This is also a very very bad practice:

Code:

---

    }//end for
    }//end if
    }//end while

---

If you have to write what the curly bracket is for then you're doing it wrong.
Learn about indentation and how each open curly bracket means the following code is tabbed out further and each closing curly bracket means that code is following tabbed out less. This is the first thing you need to get right when you start programming. It is not something to just get right later.

Additionally:

1. Casting Malloc==BAD
2. How to indent