Thread: funcion runs 14 times, then program crashes

Hey all.

The aim of this program gets a string that doesn't contain the word "every", breaks up the string into 2 strings, appends "every" onto the first string, then appends the second string onto the first(modified string).

Here's the compilable code.

Code:

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

#define FILELINELENGTH 1000		
#define NUMBEROFFILES 1000		
#define FILENAMELENGTH 100	

#define STRING1LENGTH 200
#define STRING2LENGTH 600

void insertstring(void);
char *p_searchtext = " every ";		// string to search for in a file
FILE *p_openfile;
char *p_line1;

int main(void)
{ 	
	struct data {
        char storefilename[FILENAMELENGTH];		
		char filename1[FILENAMELENGTH];			
		char filename2[FILENAMELENGTH];			
    } LineData[NUMBEROFFILES];

	int lastfilenumber1, lastfilenumber2;
	char *p_line;						
	char *p_newline;
    int  counter;						
	int	 counter1 = 0;					
	int	 counter2 = 0;					
	char *p_searchstring;
							
	system("dir /b c:\\testwebsite\\*.html > directorylisting.txt");

    if((p_openfile = fopen("directorylisting.txt", "rt")) == NULL)
    {
        perror("directorylisting.txt");
        exit( EXIT_FAILURE );
    } 
    counter = 0;

	// Copy the filenames from the file to the array; replace the newline character with a terminating
	// null character to make it a string which can be opened by fopen().

    while((fgets(LineData[counter].storefilename, FILENAMELENGTH, p_openfile) != NULL) && (counter < NUMBEROFFILES))
	{
		if((p_newline = strchr(LineData[counter].storefilename, '\n')) != NULL)
			*p_newline = '\0';

        counter++;	
		lastfilenumber1 = counter;
    }
    fclose(p_openfile);

	if((p_line = malloc(FILELINELENGTH * sizeof(char))) == NULL )
	{
		perror("Error allocating memory");
		exit (EXIT_FAILURE);
	}

	// Open up a file, search for p_searchtext, if it exists, store filename(LineData[counter].storefilename)
	// in LineData[counter2].filename1. Open up next file etc.

	for( counter = 0; counter < lastfilenumber1; counter++) 
	{	
		int found = 0;
		if((p_openfile = fopen(LineData[counter].storefilename, "r")) == NULL)
		{
			printf("error opening file: %s", LineData[counter].storefilename);
			exit(EXIT_FAILURE);
		}

		while((fgets(p_line, FILELINELENGTH, p_openfile)) != NULL) 	//// search string found
		{
			if((p_searchstring = strstr(p_line, p_searchtext) != NULL))
			{
				strcpy(LineData[counter1].filename1, LineData[counter].storefilename);
				found = 1;
				counter1++;
				break;
			}
		}

		if(!found) // search string NOT found
		{
			strcpy(LineData[counter2].filename2, LineData[counter].storefilename);
			rewind(p_openfile);
			insertstring();
			counter2++;
		}
		fclose(p_openfile);
	}
	free(p_line);

	printf("\nThere are %d files containing the search string\n", counter1);
	printf("\nThere are %d files NOT containing the search string\n", counter2);

    return 0;
}

void insertstring(void)
{
	char *p_searchstring = "lists";
	char storestring[FILELINELENGTH];
	char string1[STRING1LENGTH];
	char string2[STRING2LENGTH];
	char *location;
	int cursorposition;
	int counter = 0;

	while((fgets(storestring, FILELINELENGTH, p_openfile)) != NULL) 	
	{
		if((location = strstr(storestring, p_searchstring)) != NULL) 
		{
			cursorposition = location - storestring;
			break;
		}
	}

	memmove(string1, storestring, cursorposition+5);  // 5 is to allow space for the string "lists"
	string1[cursorposition+5] = '\0';
	strcat(string1, p_searchtext);

	for(counter = (cursorposition+5); storestring[counter] != '\0'; counter++)	
		string2[counter - (cursorposition+5)] = storestring[counter];   // copy string into the start of string2

	string2[counter - (cursorposition+5)] = '\0';
	strcat(string1, string2);
	printf("%s", string1);
}

When I run this program in debugger, after the insertstring runs 14 times, the program crashes. A debugger window pops up with:

Unhandled Exception at 0x7c90e8b6(ntdll.dll) in testing.exe: 0xC0000005: Access violation writing location 0x00030ffc

When I click the "break" button, another window pops up with:

There is no source code available for the current location

And then there is a button to "Show Disassembly", but I don't know what that does.

Can anyone offer a guess as to why the program would behaviour in this manner?

Thanks in advance.

PS: I've made some variables global because I am experimenting with variable scope.

Indentation Disclaimer
Sometimes weird translation happens when I post my code from VC++ 2008 into a forum thread. The indentations are magnified by an order of magnitude, which pushes the code far to the right of the screen. My indentation is good, but the weird translation makes it look bad. It's not my fault. Honest.