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Everytime I run the program, this mysterious error pops up saying that I have some type of status access violation. I have tried googling it and all it comes up with is that I might be trying to access some memory that is not allowed. Help would be highly appreciated!
Here is the error when I run the program:
2 [main] a 5772 exception::handle: Exception: STATUS_ACCESS_VIOLATION
1532 [main] a 5772 open_stackdumpfile: Dumping stack trace to a.exe.stackdump
Here is the .cpp code:
int main()
{
Stack s; //variable declarations
StackItem *newItem;
char token, nextChar, prevChar, response, check;
int lineCount, apostCount;
char filename[50];
bool insideComment = false, insideString = false, error, isMatch, delimError = false;
fstream sourceFile;
do //do while response is 'y'
{
do //do while opening the source file fails
{
cout << "Enter filename of source file: ";
cin.getline (filename,51);
sourceFile.open(filename); //opens the file with given filename
if (sourceFile.fail())
cout << "File could not be opened" << endl; //error if can't open
sourceFile.clear();
}
while (sourceFile.fail()); //exits if source file doesn't fail
sourceFile.clear();
lineCount = 0; //initializes line count to zero
while (!sourceFile.eof()) //exits if end of source file is reached
{
sourceFile.get(nextChar); //gets the next character in file
if ((int)nextChar == '\n') //if next character is an end line
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
else if (nextChar == '{' || nextChar == '[' || nextChar == '(')
{ //continues if next char is an opening token
newItem->token = nextChar; //sets newItem's token
newItem->lineNumber = lineCount; //sets newItem's line count
if (!s.isFull()) //continues if stack isn't full
s.push(newItem); //pushes newItem onto the stack
s.displayStack(); //displays the stack
}
else if (nextChar == '}' || nextChar == ']' || nextChar == ')')
{ //continues if next char is a closing token
if (!s.isEmpty()) //continues if stack isn't empty
{
isMatch = s.matchStack(nextChar); //checks if token matches top
if (isMatch == true) //if true, pops the top of the stack
s.pop();
else //continues if match is false
{
newItem->token = nextChar; //sets newItem's token
newItem->lineNumber = lineCount; //sets newITem's line count
s.trailingItem(newItem); //calls the trailingItem function
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //asks user whether to continue
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response;
}
break; //leaves the while loop
}
}
else if (s.isEmpty()) //continues if stack is empty
{
newItem->token = nextChar; //sets newItem's token
newItem->lineNumber = lineCount; //sets newItem's line count
s.push(newItem); //pushes newItem onto the top of the stack
s.processStack(); //processes the error
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //asks user whether to continue
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //gets user input
}
break; //leaves the while loop
}
s.displayStack(); //displays the items on the stack
}
else if (nextChar == '/') //continues if next char is a '/'
{
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '*') //continues if next char is a '*'
{ //at this point a comment has started because of '/' then '*'
insideComment = true; //sets bool to true
newItem->token = 'c'; //sets newItem's token to c for "comment"
newItem->lineNumber = lineCount; //sets newItem's line count
s.push(newItem); //pushes the item onto the stack
while (insideComment == true && !sourceFile.eof())
{ //continues while inside a comment and end of file isn't reached
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '*') //continues if next char is *
{
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '/') //continues if next char is '/'
{ //at this point the comment has ended because of '*' then '/'
insideComment = false; //sets bool to false
s.pop(); //pops off the c in the stack
}
}
}
}
else if (nextChar == '/') //continues if next char is a '/'
{ //at this point a comment has started because of / then another '/'
insideComment = true; //sets bool to true
while (insideComment == true && !sourceFile.eof())
{ //continues while inside a comment and not at end of file
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '\n') //leaves comment if next line is entered
insideComment = false; //sets bool to false
}
}
}
else if (nextChar == '\n') //continues if next char is an end line
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
else if (nextChar == '\"' && insideComment == false)
{ //continues if next char is a " and is not currently inside a comment
insideString = true; //sets bool to true b/c " starts a string
while (insideString == true && !sourceFile.eof())
{
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '\"')
insideString = false;
else if (nextChar == '\n')
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
}
}
else if (nextChar == '\'' && insideComment == false && insideString == false)
{ //continues if next char is a ' and not in a comment or string
apostCount = 1; //initializes apostrophe count (chars after first apostrophe)
while (nextChar != '\'' && !sourceFile.eof())
{ //continues while next char isn't another ' and not end of file
sourceFile.get(nextChar); //gets the next character in file
prevChar = nextChar;
apostCount++; //increments apostrophe count
if (nextChar == '\'' && prevChar == '\\' && apostCount <= 3)
nextChar = ' '; //sets next char to space if 3 or more apostrophes
else if (nextChar == '\n') //continues if next char is an end line
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
}
if (apostCount >= 4) //if more than 3 chars come after apostrophe
{ //displays delimeter error
cout << "Character delimeter error on line " << lineCount << endl;
delimError = true;
}
if (delimError == true) //continues if delimiter error occured
break; //leaves 2nd while loop
}
} //end of while loop
if (s.isEmpty() == true) //continues if no errors within stack
{ //displays successful nesting structure to user
cout << "Source file of " << lineCount << " lines has proper nesting structure";
cout << endl << endl << "Process another file? (y/n): "; //asks to continue
cin >> response; //gets user's response
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //gets user input
}
}
else //continues if errors are present
{
s.processStack(); //processes and displays the delimiter errors
cout << endl << endl << "Process another file? (y/n): "; //asks to continue
cin >> response; //gets user's response
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //gets user input
}
}
}
while (response == 'y'); //opens another file if user entered y for yes
return 0; //quits program
}
Here is the .h code:
struct StackItem //defines StackItem structure
{
char token; //holds delimeter
int lineNumber; //holds the line number of the delimeter in the source file
StackItem *next; //points to the next structure
};
typedef StackItem* nodePtr;
const int MAX_ITEMS = 99;
class Stack //Stack class definition
{
private:
nodePtr top; //points to the top of the stack
int numberItems; //number of items in the stack
public:
Stack() //initializes private variables
{ top = NULL; numberItems = 0; }
~Stack()
{ while (numberItems > 0)
{ pop();
}
}
bool isEmpty() //returns whether the stack is empty or not
{ return top == NULL; }
bool isFull() //returns whether the stack is full or not
{ return MAX_ITEMS == numberItems;}
void push(nodePtr newItem) //pushes a new item onto the top of the stack
{
newItem->next = top;
top = newItem;
numberItems++;
}
void pop() //removes the item on top of the stack
{
nodePtr p = top; //sets pointer p to what top points to
top = top->next; //top is set to the next struct in stack
delete p; //deletes the top item in the stack
numberItems--;
}
void displayStack() //displays all of the items on the stack
{
nodePtr p = top; //sets pointer p to what top points to
cout << "Stack Contents: " << endl;
while(p != NULL) //while loop to display the stack contents
{
cout << p->token << " on line " << p->lineNumber << "." << endl;
p = p->next;
}
}
void processStack() //displays the error for each delimeter in stack
{
nodePtr p = top; //sets pointer p to what top points to
while (p != NULL) //continues until p points to NULL
{
cout << "\" " << p->token << " \" on line " << setw(5) << right;
cout << p->lineNumber << " has no matching element" << endl;
p = p->next;
}
}
//determines whether the stack delimeter matches the current character
bool matchStack(char character)
{
bool match = false;
if (top->token == '{')
{
if (character == '}')
match = true; //sets bool to true if we have { and }
}
else if (top->token == '[')
{
if (character == ']')
match = true; //sets bool to true if we have [ and ]
}
else if (top->token == '(')
{
if (character == ')')
match = true; //sets bool to true if we have ( and )
}
return match; //returns the bool
}
//called if we have a trailing item that doesn't match stack delimeter
void trailingItem(nodePtr newItem) //displays what doesn't match
{
cout << "\" " << top->token << " \" on line " << setw(5) << right;
cout << top->lineNumber << " doesn't match \" " << newItem->token;
cout << " \" on line " << setw(5) << right << newItem->lineNumber;
}
};
Here is the a.exe.stackdump file:
Exception: STATUS_ACCESS_VIOLATION at eip=00401701
eax=61100049 ebx=0028CD40 ecx=00A01998 edx=00000000
esi=0028CD40 edi=00000000 ebp=0028CD18 esp=0028CAF0
program=C:\Users\Tyler\Desktop\Program 2\a.exe, pid 5772, thread main
cs=0023 ds=002B es=002B fs=0053 gs=002B ss=002B
Stack trace:
Frame Function Args
0028CD18 00401701 (00000001, 009E8628, 009E8510, 00000001)
0028CD68 61007038 (00000000, 0028CDA4, 61006980, 7EFDE000)
End of stack trace
877
You declare StackItem *newItem; that is a pointer, but you never initialize it to anything, so its contents are undefined.
Then, as soon as you do newItem->... your program will crash, as it is not pointing to any valid memory.
The solution would be along the lines of adding a few newItem = new StackItem here and there to create the actual objects. And naturally a constructor (or several) to the StackItem class would be most welcome.
116
You have not initialized the newItem pointer, but are dereferencing it.
Also, you told cin.getline that a 50 byte character is 51 bytes wide.
Just two problems I spotted at a casual glance.
4
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