Print List function is not outputting data from CSV file - c++

Question

I am working on a Linked List assignment. The Load Bids function extracts the data from the CSV file. The Print List function is supposed to print all the bid entries in the list to the console. For some reason, whenever I select the Load Bids option, and then the Print List option from menu, the Print List function is not outputting data, even after I call the Load Bids function. It just prints the default values from the default constructor, which is basically nothing. The Print List function seems to be written correctly, but the data appears to be getting lost somewhere. Can someone help me with this?
#include <algorithm>
#include <iostream>
#include <time.h>
#include "CSVparser.hpp"
using namespace std;
//============================================================================
// Global definitions visible to all methods and classes
//============================================================================
// forward declarations
double strToDouble(string str, char ch);
// define a structure to hold bid information
struct Bid {
string bidId; // unique identifier
string title;
string fund;
double amount;
Bid() {
amount = 0.0;
}
};
//============================================================================
// Linked-List class definition
//============================================================================
/**
* Define a class containing data members and methods to
* implement a linked-list.
*/
class LinkedList {
private:
//Internal structure for list entries, housekeeping variables
struct Node {
Bid bid;
Node *next;
// default constructor
Node() {
next = nullptr;
}
// initialize with a bid
Node(Bid aBid) {
bid = aBid;
next = nullptr;
}
};
Node* head;
Node* tail;
int size = 0;
public:
LinkedList();
virtual ~LinkedList();
void Append(Bid bid);
void Prepend(Bid bid);
void PrintList();
void Remove(string bidId);
Bid Search(string bidId);
int Size();
};
/**
* Default constructor
*/
LinkedList::LinkedList() {
// FIXME (1): Initialize housekeeping variables
//set head and tail equal to null
head = nullptr;
tail = nullptr;
}
/**
* Destructor
*/
LinkedList::~LinkedList() {
// start at the head
Node* current = head;
Node* temp;
// loop over each node, detach from list then delete
while (current != nullptr) {
temp = current; // hang on to current node
current = current->next; // make current the next node
delete temp; // delete the orphan node
}
}
/**
* Append a new bid to the end of the list
*/
void LinkedList::Append(Bid bid) {
// FIXME (2): Implement append logic
//Create new node
Node* new_node = new Node;
//if there is nothing at the head...
if (head == nullptr) {
// new node becomes the head and the tail
head = new_node;
tail = new_node;
}
//else
else {
// make current tail node point to the new node
tail->next = new_node;
// and tail becomes the new node
tail = new_node;
}
//increase size count
size++;
}
/**
* Prepend a new bid to the start of the list
*/
void LinkedList::Prepend(Bid bid) {
// FIXME (3): Implement prepend logic
// Create new node
Node* new_node = new Node;
// if there is already something at the head...
if (head != nullptr) {
// new node points to current head as its next node
new_node->next = head;
}
// head now becomes the new node
head = new_node;
//increase size count
size++;
}
/**
* Simple output of all bids in the list
*/
void LinkedList::PrintList() {
// FIXME (4): Implement print logic
// start at the head
Node* current = head;
// while loop over each node looking for a match
while (current != nullptr) {
//output current bidID, title, amount and fund
cout << current->bid.bidId << " | ";
cout << current->bid.title << " | ";
cout << current->bid.amount << " | ";
cout << current->bid.fund << endl;
//set current equal to next
current = current->next;
}
}
/**
* Remove a specified bid
*
* #param bidId The bid id to remove from the list
*/
void LinkedList::Remove(string bidId) {
// FIXME (5): Implement remove logic
// special case if matching node is the head
if (head->bid.bidId == bidId) {
// make head point to the next node in the list
head->next;
//decrease size count
size--;
//return
return;
}
// start at the head
Node* current = head;
Node* temp = nullptr;
// while loop over each node looking for a match
while (current != nullptr) {
// if the next node bidID is equal to the current bidID
if (current->next->bid.bidId == current->bid.bidId) {
// hold onto the next node temporarily
temp = current->next;
}
// make current node point beyond the next node
current->next->next;
// now free up memory held by temp
free(temp);
// decrease size count
size--;
//return
return;
}
// curretn node is equal to next node
current = current->next;
}
/**
* Search for the specified bidId
*
* #param bidId The bid id to search for
*/
Bid LinkedList::Search(string bidId) {
// FIXME (6): Implement search logic
// special case if matching node is the head
if (head->bid.bidId == bidId) {
// make head point to the next node in the list
head->next;
//decrease size count
size--;
//return
return head->bid;
}
// start at the head of the list
Node* current = head;
// keep searching until end reached with while loop (next != nullptr
while (current != nullptr) {
// if the current node matches, return it
if (current->bid.bidId == bidId) {
return current->bid;
}
// else current node is equal to next node
else {
current = current->next;
}
}
//return bid
return current->bid;
}
/**
* Returns the current size (number of elements) in the list
*/
int LinkedList::Size() {
return size;
}
//============================================================================
// Static methods used for testing
//============================================================================
/**
* Display the bid information
*
* #param bid struct containing the bid info
*/
void displayBid(Bid bid) {
cout << bid.bidId << ": " << bid.title << " | " << bid.amount
<< " | " << bid.fund << endl;
return;
}
/**
* Prompt user for bid information
*
* #return Bid struct containing the bid info
*/
Bid getBid() {
Bid bid;
cout << "Enter Id: ";
cin.ignore();
getline(cin, bid.bidId);
cout << "Enter title: ";
getline(cin, bid.title);
cout << "Enter fund: ";
cin >> bid.fund;
cout << "Enter amount: ";
cin.ignore();
string strAmount;
getline(cin, strAmount);
bid.amount = strToDouble(strAmount, '$');
return bid;
}
/**
* Load a CSV file containing bids into a LinkedList
*
* #return a LinkedList containing all the bids read
*/
void loadBids(string csvPath, LinkedList *list) {
cout << "Loading CSV file " << csvPath << endl;
// initialize the CSV Parser
csv::Parser file = csv::Parser(csvPath);
try {
// loop to read rows of a CSV file
for (int i = 0; i < file.rowCount(); i++) {
// initialize a bid using data from current row (i)
Bid bid;
bid.bidId = file[i][1];
bid.title = file[i][0];
bid.fund = file[i][8];
bid.amount = strToDouble(file[i][4], '$');
// cout << bid.bidId << ": " << bid.title << " | " << bid.fund << " | " <<
bid.amount << endl;
// add this bid to the end
list->Append(bid);
}
} catch (csv::Error &e) {
std::cerr << e.what() << std::endl;
}
}
/**
* Simple C function to convert a string to a double
* after stripping out unwanted char
*
* credit: http://stackoverflow.com/a/24875936
*
* #param ch The character to strip out
*/
double strToDouble(string str, char ch) {
str.erase(remove(str.begin(), str.end(), ch), str.end());
return atof(str.c_str());
}
/**
* The one and only main() method
*
* #param arg[1] path to CSV file to load from (optional)
* #param arg[2] the bid Id to use when searching the list (optional)
*/
int main(int argc, char* argv[]) {
// process command line arguments
string csvPath, bidKey;
switch (argc) {
case 2:
csvPath = argv[1];
bidKey = "98109";
break;
case 3:
csvPath = argv[1];
bidKey = argv[2];
break;
default:
csvPath = "eBid_Monthly_Sales_Dec_2016.csv";
bidKey = "98109";
}
clock_t ticks;
LinkedList bidList;
Bid bid;
int choice = 0;
while (choice != 9) {
cout << "Menu:" << endl;
cout << " 1. Enter a Bid" << endl;
cout << " 2. Load Bids" << endl;
cout << " 3. Display All Bids" << endl;
cout << " 4. Find Bid" << endl;
cout << " 5. Remove Bid" << endl;
cout << " 9. Exit" << endl;
cout << "Enter choice: ";
cin >> choice;
switch (choice) {
case 1:
bid = getBid();
bidList.Append(bid);
displayBid(bid);
break;
case 2:
ticks = clock();
loadBids(csvPath, &bidList);
cout << bidList.Size() << " bids read" << endl;
ticks = clock() - ticks; // current clock ticks minus starting clock ticks
cout << "time: " << ticks << " milliseconds" << endl;
cout << "time: " << ticks * 1.0 / CLOCKS_PER_SEC << " seconds" << endl;
break;
case 3:
bidList.PrintList();
break;
case 4:
ticks = clock();
bid = bidList.Search(bidKey);
ticks = clock() - ticks; // current clock ticks minus starting clock ticks
if (!bid.bidId.empty()) {
displayBid(bid);
} else {
cout << "Bid Id " << bidKey << " not found." << endl;
}
cout << "time: " << ticks << " clock ticks" << endl;
cout << "time: " << ticks * 1.0 / CLOCKS_PER_SEC << " seconds" << endl;
break;
case 5:
bidList.Remove(bidKey);
break;
}
}
cout << "Good bye." << endl;
return 0;
}

Answer 1

I altered the Append function by adding a couple of lines after creating the new node and it looks like the problem was solved. Here is the new function.
void LinkedList::Append(Bid bid) {
// FIXME (2): Implement append logic
//Create new node
Node* new_node = new Node;
new_node->bid = bid;
new_node->next = nullptr;
//if there is nothing at the head...
if (head == nullptr) {
// new node becomes the head and the tail
head = new_node;
tail = new_node;
}
//else
else {
// make current tail node point to the new node
tail->next = new_node;
// and tail becomes the new node
tail = new_node;
}
//increase size count
size++;
}