The HashTable.cpp program is partially completed. It contains
empty methods representing the programming interface used to
interact with a hash table. I need some help with adding
logic to the methods to implement the necessary behavior. I have
set the parts I am confused with in Bold. Here is the public
API for HashTable.cpp that I need to have to complete:
public:
HashTable();
virtual ~HashTable();
void Insert(Bid bid);
void PrintAll();
void Remove(string bidId);
Bid Search(string bidId);
#include <algorithm>
#include <climits>
#include <iostream>
#include <string> // atoi
#include <time.h>
#include "CSVparser.hpp"
using namespace std;
const unsigned int DEFAULT_SIZE = 179;
// 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;
}
};
/**
* Define a class containing data members and methods to
* implement a hash table with chaining.
*/
class HashTable {
private:
// Define structures to hold bids
struct Node {
Bid bid;
unsigned int key;
Node *next;
// default constructor
Node() {
key = UINT_MAX;
next = nullptr;
}
// initialize with a bid
Node(Bid aBid) : Node() {
bid = aBid;
}
// initialize with a bid and a
key
Node(Bid aBid, unsigned int aKey) :
Node(aBid) {
key = aKey;
}
};
vector<Node> nodes;
unsigned int tableSize = DEFAULT_SIZE;
unsigned int hash(int key);
public:
HashTable();
HashTable(unsigned int size);
virtual ~HashTable();
void Insert(Bid bid);
void PrintAll();
void Remove(string bidId);
Bid Search(string bidId);
};
/**
* Default constructor
*/
HashTable::HashTable() {
// FIXME (1): Initialize the structures used
to hold bids
// Initalize node structure by resizing
tableSize
}
/**
* Constructor for specifying size of the table
* Use to improve efficiency of hashing algorithm
* by reducing collisions without wasting memory.
*/
HashTable::HashTable(unsigned int size) {
// invoke local tableSize to size with
this->
// resize nodes size
}
/**
* Destructor
*/
HashTable::~HashTable() {
// FIXME (2): Implement logic to free storage
when class is destroyed
// erase nodes beginning
}
/**
* Calculate the hash value of a given key.
* Note that key is specifically defined as
* unsigned int to prevent undefined results
* of a negative list index.
*
* @param key The key to hash
* @return The calculated hash
*/
unsigned int HashTable::hash(int key) {
// FIXME (3): Implement logic to calculate a
hash value
// return key tableSize
}
/**
* Insert a bid
*
* @param bid The bid to insert
*/
void HashTable::Insert(Bid bid) {
// FIXME (5): Implement logic to insert a
bid
// create the key for the given bid
// retrieve node using key
// if no entry found for the key
// assign this node to the key
position
// else if node is not used
// assing old node key to
UNIT_MAX, set to key, set old node to bid and old node next to null
pointer
// else find the next open node
// add new newNode to
end
}
/**
* Print all bids
*/
void HashTable::PrintAll() {
// FIXME (6): Implement logic to print all
bids
// for node begin to end iterate
// if key not equal to UINT_MAx
// output key, bidID,
title, amount and fund
// node is equal to next
iter
// while node not equal
to nullptr
// output
key, bidID, title, amount and fund
// node is
equal to next node
}
/**
* Remove a bid
*
* @param bidId The bid id to search for
*/
void HashTable::Remove(string bidId) {
// FIXME (7): Implement logic to remove a
bid
// set key equal to hash atoi bidID cstring
// erase node begin and key
}
/**
* Search for the specified bidId
*
* @param bidId The bid id to search for
*/
Bid HashTable::Search(string bidId) {
Bid bid;
// FIXME (8): Implement logic to search
for and return a bid
// create the key for the given bid
// if entry found for the key
//return node bid
// if no entry found for the key
// return bid
// while node not equal to nullptr
// if the current node matches, return
it
//node is equal to next
node
return bid;
}
//============================================================================
// Static methods used for testing
//============================================================================
/**
* Display the bid information to the console (std::out)
*
* @param bid struct containing the bid info
*/
void displayBid(Bid bid) {
cout << bid.bidId << ": " <<
bid.title << " | " << bid.amount << " | "
<< bid.fund
<< endl;
return;
}
/**
* Load a CSV file containing bids into a container
*
* @param csvPath the path to the CSV file to load
* @return a container holding all the bids read
*/
void loadBids(string csvPath, HashTable* hashTable) {
cout << "Loading CSV file " << csvPath
<< endl;
// initialize the CSV Parser using the given
path
csv::Parser file = csv::Parser(csvPath);
// read and display header row - optional
vector<string> header = file.getHeader();
for (auto const& c : header) {
cout << c << " | ";
}
cout << "" << endl;
try {
// loop to read rows of a CSV
file
for (unsigned int i = 0; i <
file.rowCount(); i++) {
// Create a data
structure and add to the collection of bids
Bid bid;
bid.bidId =
file[1];
bid.title =
file[0];
bid.fund =
file[8];
bid.amount =
strToDouble(file[4], '$');
//cout << "Item:
" << bid.title << ", Fund: " << bid.fund <<
", Amount: " << bid.amount << endl;
// push this bid to
the end
hashTable->Insert(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
*/
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";
}
// Define a timer variable
clock_t ticks;
// Define a hash table to hold all the bids
HashTable* bidTable;
Bid bid;
bidTable = new HashTable();
int choice = 0;
while (choice != 9) {
cout << "Menu:" <<
endl;
cout << " 1. Load Bids"
<< endl;
cout << " 2. Display All
Bids" << endl;
cout << " 3. Find Bid"
<< endl;
cout << " 4. Remove Bid"
<< endl;
cout << " 9. Exit" <<
endl;
cout << "Enter choice: ";
cin >> choice;
switch (choice) {
case 1:
// Initialize a timer
variable before loading bids
ticks = clock();
// Complete the method
call to load the bids
loadBids(csvPath,
bidTable);
// Calculate elapsed
time and display result
ticks = clock() - ticks;
// current clock ticks minus starting clock ticks
cout << "time: "
<< ticks << " clock ticks" << endl;
cout << "time: "
<< ticks * 1.0 / CLOCKS_PER_SEC << " seconds" <<
endl;
break;
case 2:
bidTable->PrintAll();
break;
case 3:
ticks = clock();
bid =
bidTable->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 4:
bidTable->Remove(bidKey);
break;
}
}
cout << "Good bye." << endl;
return 0;
}
The HashTable.cpp program is partially completed. It contains empty methods representing the programming interface used
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