I have a C++ program that reads from an infile, determines by a char if the line should be Deleted or Added. From there the program uses pointers to insert data into a sorted list. The issue I am having is printing the data out properly
If you notice, I have to determine if the item is valid or not so i pass it through a validation function. It prints the invalid file in the proper place, but also prints lines that arent wanted under invalid. It then prints the lines out under where they should be, without the invalid file like it should, but it repeats the lines over and over.
I have been trying to figure it out, I believe my problem is in how I use my while statements... Any ideas??
A second issue I am having (one less important than the 1st) is when I put D in the infile to delete and ./a.out, it gives me a segmentation error. I must have some logic wrong with my coding for the delete portion... hmm...
Here is the code provided by the prof (somewhat edited to add what changes i needed to make)
.h and .cxx (driver below)
#include <iostream>
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
struct ItemType
{
int id;
float gpa;
char major[2];
};
struct NodeType
{
ItemType info;
NodeType* next;
};
class SortedType
{
public:
SortedType();
// Constructor
// Postcondition: Empty list is created
~SortedType();
// Destructor
// Postcondition: List is destroyed
SortedType(const SortedType& otherList);
// Copy-constructor
// Postcondition: List is created as a duplicate of otherList
bool IsFull() const;
// Determines whether list is full.
// Post: Function value = (list is full)
bool invalidItem(ItemType item) const;
int LengthIs() const;
// Determines the number of elements in list.
// Post: Function value = number of elements in list.
void MakeEmpty();
// Initializes list to empty state.
// Post: List is empty.
void RetrieveItem(ItemType& item, bool& found);
// Retrieves list element whose key matches item's key
// (if present).
// Pre: Key member of item is initialized.
// Post: If there is an element someItem whose key matches
// item's key, then found = true and item is a copy
// of someItem; otherwise found = false and item is
// unchanged.
// List is unchanged.
void InsertItem(ItemType item);
// Adds item to list.
// Pre: List is not full.
// item is not in list.
// Post: item is in list
// (added) // list order is preserved
void DeleteItem(ItemType item);
// Deletes the element whose key matches item's key.
// Pre: Key member of item is initialized.
// One and only one element in list has a key matching
// item's key.
// Post: No element in list has a key matching item's key.
void ResetList();
// Initializes current position to end of list for iteration
// through list.
// Post: Current position is at end of list.
void GetNextItem(ItemType& item);
// Gets the next element in list.
// Pre:
// Post: If Current position is at end, currentPos points to head of list,
// else item is copy of element at current position.
// Advance current position.
void Print(ofstream&);
private:
NodeType* listData;
int length;
NodeType* currentPos;
};
void GetNextItem(ItemType& item);
// Gets the next element in list.
// Pre:
// Post: If Current position is at end, currentPos points to head of list,
// else item is copy of element at current position.
// Advance current position.
void Print(ofstream&);
private:
NodeType* listData;
int length;
NodeType* currentPos;
};
// SortedType.cxx
SortedType::SortedType() // Class constructor
{
length = 0;
listData = NULL;
}
SortedType::~SortedType()
// Post: List is empty; all items have been deallocated.
{
MakeEmpty();
}
SortedType::SortedType(const SortedType& otherList)
// Copy-constructor
// Postcondition:
// IF otherList.listData == NULL
// listData == NULL
// ELSE
// listData points to a new linked list that is a copy of
// the linked list pointed to by otherList.listData
{
NodeType* fromPtr; // Pointer into list being copied from
NodeType* toPtr; // Pointer into new list being built
if(otherList.listData == NULL)
{
listData = NULL;
return;
}
// Copy first node
fromPtr = otherList.listData;
listData = new NodeType;
listData->info = fromPtr->info;
// Copy remaining nodes
toPtr = listData;
fromPtr = fromPtr->next;
while (fromPtr != NULL)
{
toPtr->next = new NodeType;
toPtr = toPtr->next;
toPtr->info = fromPtr->info;
fromPtr = fromPtr->next;
}
toPtr->next = NULL;
}
/* bool SortedType::IsFull() const
// Returns true if there is no room for another ItemType
// on the free store; false otherwise.
{
NodeType* location;
try
{
location = new NodeType;
delete location;
return false;
}
catch(bad_alloc exception)
{
return true;
}
} */
bool SortedType::invalidItem(ItemType item) const
//**********************************************************************
//Purpose: Determines whether the data assigned is valid given the parameters
//Input: item.id, gpa, major
//Pre: Variables must be set and have valid numbers
//output: bool, true or false
//post: so long as function runs, the data will be processed and determined
// as invalid or valid data
//note: None
//**********************************************************************
{
return(item.id >= 111 && item.id <= 999 &&
item.gpa >= 0.0 && item.gpa <= 4.0 &&
item.major[0] == 'C' || item.major[0] == 'I' &&
item.major[1] == 'S');
}
bool SortedType::IsFull() const
// Returns true if there is no room for another ItemType
// object on the free store; false otherwise.
{
NodeType* ptr;
ptr = new NodeType;
if (ptr == NULL)
return true;
else
{
delete ptr;
return false;
}
}
int SortedType::LengthIs() const
// Post: Number of items in the list is returned.
{
return length;
}
void SortedType::MakeEmpty()
// Post: List is empty; all items have been deallocated.
{
NodeType*
tempPtr;
while (listData != NULL) // traverse list, deallocating each node in turn
{
tempPtr = listData;
listData = listData->next;
delete tempPtr;
}
length = 0; // to agree with the fact that all nodes are deallocated
}
void SortedType::DeleteItem(ItemType item)
// Pre: item's key has been initialized.
// An element in the list has a key that matches item's.
// Post: No element in the list has a key that matches item's.
{
NodeType* location = listData;
NodeType* tempLocation;
// Locate node to be deleted.
if (item.id == listData->info.id)
{
tempLocation = location;
listData = listData->next; // Delete first node.
}
else
{
while (!(item.id==(location->next)->info.id))
location = location->next;
// Delete node at location->next
tempLocation = location->next;
location->next = (location->next)->next;
}
delete tempLocation;
length--;
}
void SortedType::ResetList()
// Post: Current position has been initialized to AtEnd
{
currentPos = NULL;
}
void SortedType::RetrieveItem(ItemType& item, bool& found)
{
bool moreToSearch;
NodeType* location;
location = listData;
found = false;
moreToSearch = (location != NULL);
while (moreToSearch && !found)
{
if (location->info.id < item.id)
{
location = location->next;
moreToSearch = (location != NULL);
}
else if (item.id == location->info.id)
{
found = true;
item = location->info;
}
else
moreToSearch = false;
}
}
void SortedType::InsertItem(ItemType item)
{
NodeType* newNode; // pointer to node being inserted
NodeType* predLoc; // trailing pointer
NodeType* location; // traveling pointer
bool moreToSearch;
location = listData;
predLoc = NULL;
moreToSearch = (location != NULL);
// Find insertion point.
while (moreToSearch)
{
if (location->info.id < item.id)
{
predLoc = location;
location = location->next;
moreToSearch = (location != NULL);
}
else
moreToSearch = false;
// Prepare node for insertion
newNode = new NodeType;
newNode->info = item;
// Insert node into list.
if (predLoc == NULL) // Insert as first
{
newNode->next = listData;
listData = newNode;
}
else
{
newNode->next = location;
predLoc->next = newNode;
}
length++;
}
void SortedType::GetNextItem(ItemType& item)
// Pre: Current position is defined.
// Element at current position is not last in list.
// Post: Current position has been updated; item is current item.
{
if (currentPos == NULL) //Wrap at end of list
currentPos = listData;
item = currentPos->info;
currentPos = currentPos->next;
}
void SortedType::Print(ofstream& outFile)
{
currentPos = listData;
while(currentPos != NULL)
{
outFile << currentPos->info.id << " " << currentPos->info.gpa << currentPos->info.major[0] << currentPos->info.major[1]
currentPos = currentPos->next;
}
}Here is the driver for the above
#include "SortedLinkedList.h"
int main()
{
ifstream inFile;
ofstream outFile;
char lister;
int length = 0;
inFile.open("in.data");
outFile.open("out.data");
if(inFile.fail() || outFile.fail())
{
cout << "Input or output file opening failed" << endl;
}
SortedType ReadList;
ItemType item;
outFile << "<~~~~~~~ Grade Report ~~~~~~~>" << endl;
ReadList.MakeEmpty();
inFile >> lister;
while(inFile)
{
if(lister == 'A')
{
inFile >> item.id >> item.gpa >> item.major[0] >> item.major[1];
ReadList.InsertItem(item);
}
else if(lister == 'D')
{
inFile >> item.id;
ReadList.DeleteItem(item);
}
inFile >> lister;
}
ReadList.MakeEmpty();
inFile >> lister;
while(inFile)
{
if(lister == 'A')
{
inFile >> item.id >> item.gpa >> item.major[0] >> item.major[1];
ReadList.InsertItem(item);
}
else if(lister == 'D')
{
inFile >> item.id;
ReadList.DeleteItem(item);
}
inFile >> lister;
}
ReadList.ResetList();
length = ReadList.LengthIs();
for(int count = 1; count <= length; count++)
{
ReadList.GetNextItem(item);
if(!ReadList.invalidItem(item))
{
//ReadList.Print(outFile);
//outFile << item.id << setw(20) << item.gpa << setw(20) << item.major[0] << item.major[1];
outFile << " **** invalid line" << endl << endl;
ReadList.DeleteItem(item);
}
}
ReadList.ResetList();
length = ReadList.LengthIs();
outFile << "student id" << setw(12) << "GPA" << setw(22) << "Major" << endl;
outFile << "----------" << setw(12) << "---" << setw(22) <<
"-----" << endl;
for(int count = 1; count <= length; count++)
{
ReadList.GetNextItem(item);
ReadList.Print(outFile);
//outFile << item.id << setw(20) << item.gpa << setw(20) << item.major[0] << item.major[1];
//outFile << endl;
}
outFile << "> > > end < < <" << endl;
return 0;
}The driver has some things commented out as I was troubleshooting my problem and trying different things. So bear with me.
Thanks in advance for any advice or help on this problem!!!
Also, if I have any other large mistakes, point them out to me please so I can go take a look at them and make changes.
Here is a sample input file:
A 666 3.23 IS A 100 3.11 CS A 555 3.85 IS A 777 3.99 CS A 888 3.99 IS
Here is a sample output of what I get with the above code:
<~~~~~~~ Grade Report ~~~~~~~>
100 3.11CS
555 3.85IS
666 3.23IS
777 3.99CS
888 3.99IS
**** invalid line
student id GPA Major
---------- --- -----
555 3.85IS
666 3.23IS
777 3.99CS
888 3.99IS
555 3.85IS
666 3.23IS
777 3.99CS
888 3.99IS
555 3.85IS
666 3.23IS
777 3.99CS
888 3.99IS
555 3.85IS
666 3.23IS
777 3.99CS
888 3.99IS
> > > end < < <