Hi, I'm a newbie in Computer Sciences desperately trying to get some C++ homework help! I've gone to many tutors, I've asked my classmates, and they were unable to help me (or not willing to help me). My prof was the only one helpful but was not available on the weekend. So now I'm turning to the Internet. Desperate cries calls for desperate measures.

I'm supposed to write code for a hashmap to function. But I'm currently having problem with the get() function. When it runs, it crashes somewhere on the modulo calculation, and when I look at it, somehow by magic the capacity had been assigned a zero when I'm guessing it's not supposed to.

Here is the hashmap.h

Here is the hashmap.cpp. This is where the problem is located at (in red).Code:#pragma once #include "stock.h" class hashmap { public: hashmap(int capacity); ~hashmap(void); // Gets the stock associated with the provided stock symbol from the hashmap, // returns true if successful, false if not. // // Additional data returned: // symbolHash: result of applying hashStr() to stock symbol // hashIndex: array index produced by applying the modulo operator // to the hash value produced by hashStr() // usedIndex: array index where the stock was actually found // chainLgth: length of the linear probe chain to the stock bool get(char const * const symbol, stock& s, unsigned int& symbolHash, unsigned int& hashIndex, unsigned int& usedIndex, unsigned int& chainLgth) const; // Adds the stock to the hashmap, returns true if successful, // false if not (if the symbol is already present as a key or // if the hash table was already full). // // Additional data returned: // symbolHash: result of applying hashStr() to stock symbol // hashIndex: array index produced by applying the modulo operator // to the hash value produced by hashStr() // usedIndex: array index where the stock will actually be stored // chainLgth: length of the linear probe chain to the stock bool put(const stock& s, unsigned int& symbolHash, unsigned int& hashIndex, unsigned int& usedIndex, unsigned int& chainLgth); // Removes the stock associated with the provided symbol from the hashmap, // returns true if successful, false if not (if the symbol is not present as a key). // Returns a copy of the stock in s. // // Additional data returned: // symbolHash: result of applying hashStr() to stock symbol // hashIndex: array index produced by applying the modulo operator // to the hash value produced by hashStr() // usedIndex: array index where the stock was actually found // chainLgth: length of the linear probe chain to the stock bool remove(char const * const symbol, stock &s, unsigned int& symbolHash, unsigned int& hashIndex, unsigned int& usedIndex, unsigned int& chainLgth); friend ostream& operator<<(ostream& out, const hashmap& h); private: static unsigned int hashStr(char const * const symbol); // hashing function struct slot { enum state {empty, deleted, full}; stock slotStock; state slotState; }; slot *slots; int capacity; int nStocks; int nextIndex(int index) const; //intline void nextIndex(int& index) const; int prevIndex(int index) const; bool slotEmpty(int index) const; void setSlotEmpty(int index); };

My brother told me that it was a memory code and I should try to restart the program completely so that the problem will go away, but the problem is still there.Code:// enable Visual C++ memory leak checking #ifdef _DEBUG #include <ostream> #define _CRTDBG_MAP_ALLOC #include <crtdbg.h> #define DEBUG_NEW new(_NORMAL_BLOCK, __FILE__, __LINE__) #define new DEBUG_NEW #endif #include "hashmap.h" hashmap::hashmap(int capacity) : slots(new slot[capacity]) //constructor. This is the good constructor. No changes! { for (int i = 0; i < capacity; i++) slots[i].slotState = slot::empty; } hashmap::~hashmap(void) { delete[] slots; } bool hashmap::get(char const * const symbol, stock& s, unsigned int& symbolHash, unsigned int& hashIndex, unsigned int& usedIndex, unsigned int& chainLgth) const { /* INSTRUCTION */ // use hashStr to generate a hash code for symbol // compute array index using % or the equivalent // if slots[index] empty, stock is not present // else do linear probing to find either an empty slot or the stock we're looking for int tempIndex; symbolHash = hashStr(symbol); hashIndex = symbolHash % capacity; tempIndex = hashIndex+1; if(slots[hashIndex].slotState==slot::empty) { return false; } while(tempIndex != hashIndex) { if(tempIndex > capacity) { tempIndex = 0; } } if(slots[tempIndex].slotState==slot::empty || slots[tempIndex].slotState==slot::deleted) { return false; } if(0==strcmp(slots[tempIndex].slotStock.getSymbol(), symbol)) { { s.copyData(slots[hashIndex].slotStock); return true; } tempIndex++; } return false; } bool hashmap::put(const stock& s, unsigned int& symbolHash, unsigned int& hashIndex, unsigned int& usedIndex, unsigned int& chainLgth) { // use hashStr to generate a hash code for symbol // compute array index using % or the equivalent // if slots[index] empty, store the stock there // else do linear probing to find an empty slot return false; } bool hashmap::remove(char const * const symbol, stock& s, unsigned int& symbolHash, unsigned int& hashIndex, unsigned int& usedIndex, unsigned int& chainLgth) { return false; } unsigned int hashmap::hashStr(char const * const str) { // Hash string according to the formula in java.lang.String.hashCode(): // // str[0]*(31^(n-1)) + str[1]*(31^(n-2)) + ... + str[n-1] // // s is the array of characters, n is the number of characters in the string, // and 31^n means 31 to the nth power. // // This function is declared static because its result depends // only on the characters in the string. You will need to apply // the modulo operator to the result of this function to generate // the required table index. The place to do this is in the functions // that call this function. // // You can and should do this computation entirely with integers. In other // words, there is no need to use floating point values. In particular, you // should not use the pow() function from <math.h> in this lab. return 0; } ostream& operator<<(ostream& out, const hashmap& h) { out << "<print the contents of the hashmap>" << endl; return out; }

I'm not asking anyone to do the homework for me. I just want someone... SOMEBODY descent to help me on what I'm doing wrong and what a correct piece of code should I go for, cuz I'm totally stuck. The assignment is due very soon, and I have a big Bio test to study for on the next day, and my mind is going crazy!!

I appreciate all the help I can get to get through this. Thank you!!