Question

How to code the following function in C? (NOT C++)

int vehicleInsert(HashFile *pHashFile, Vehicle *pVehicle)

This function inserts a vehicle into the specified file.

• Determine the RBN using the driver's hash function.

• Use readRec to read the record at that RBN.

• If that location doesn't exist or the record at that location has a szVehicleId[0] == '\0': o Write this new vehicle record at that location using writeRec.

• If that record exists and that vehicle's szVehicleId matches, return RC_REC_EXISTS. (Do not update it.)

• Otherwise, return RC_SYNONYM. Note that in program #2, we will actually insert synonyms.

Answer 1

// CPP program to implement hashing with chaining 
#include<bits/stdc++.h> 
using namespace std; 

class Hash 
{ 
        int BUCKET; // No. of buckets 

        // Pointer to an array containing buckets 
        list<int> *table; 
public: 
        Hash(int V); // Constructor 

        // inserts a key into hash table 
        void insertItem(int x); 

        // deletes a key from hash table 
        void deleteItem(int key); 

        // hash function to map values to key 
        int hashFunction(int x) { 
                return (x % BUCKET); 
        } 

        void displayHash(); 
}; 

Hash::Hash(int b) 
{ 
        this->BUCKET = b; 
        table = new list<int>[BUCKET]; 
} 

void Hash::insertItem(int key) 
{ 
        int index = hashFunction(key); 
        table[index].push_back(key); 
} 

void Hash::deleteItem(int key) 
{ 
// get the hash index of key 
int index = hashFunction(key); 

// find the key in (inex)th list 
list <int> :: iterator i; 
for (i = table[index].begin(); 
                i != table[index].end(); i++) { 
        if (*i == key) 
        break; 
} 

// if key is found in hash table, remove it 
if (i != table[index].end()) 
        table[index].erase(i); 
} 

// function to display hash table 
void Hash::displayHash() { 
for (int i = 0; i < BUCKET; i++) { 
        cout << i; 
        for (auto x : table[i]) 
        cout << " --> " << x; 
        cout << endl; 
} 
} 

// Driver program 
int main() 
{ 
// array that contains keys to be mapped 
int a[] = {15, 11, 27, 8, 12}; 
int n = sizeof(a)/sizeof(a[0]); 

// insert the keys into the hash table 
Hash h(7); // 7 is count of buckets in 
                        // hash table 
for (int i = 0; i < n; i++) 
        h.insertItem(a[i]); 

// delete 12 from hash table 
h.deleteItem(12); 

// display the Hash table 
h.displayHash(); 

return 0; 
}