Hashing - How to find collision rate?

[pjesh]

Guys, I'm having issues calculating the collision rate of this table. It's currently printing out values same as the number of elements inserted. Any ideas?

#include <iostream>
#include <cstdlib>
#include "Question_3.hpp"
#include <stdint.h>

int collision = 0;

int hash(int num) {
    int key;
    key = num % 10;
    return key;
}


list::list() {
    first = last = cur = prev = NULL; 
}


void list::insert(long long int a) {
     //No collision occurance
    if (first = NULL) {

        first = new Node;
        first->data = a;
        first->next = NULL;

        last = first;
    }
    else {
         
        Node* newNode = new Node;
        newNode->data = a;
        newNode-> next = NULL;
        last = first;
        collision++;
    }
}

void list::display() {
    cur = first;
    while (cur != NULL) {
        cout << " " << cur -> data << " ";
        cur = cur-> next;
    }
    cout << endl;
}


int main()
{
    int numInserted;
    int hashvalue;
    list table[10];
    cout << "Please enter 10 elements after each element\n";

    for (int i = 0; i < 20; i++) {
        cout << "Element " << i + 1 << " -> ";

        numInserted = rand()%10;
        cout << numInserted << endl;
        //cin >> numInserted;

            table[hash(numInserted)].insert(numInserted);

    }

    system("pause");

    cout << endl;
    for (int k = 0; k<10; k++) {
        cout << "Bucket [" << k <<  "]";

        table[k].display(); 

    }

    cout << "Collsion rate: " << collision << endl;

    return 0;

[Zhuge]

Line 22 should be using ==, not =.

[pjesh]

Thanks. That solved the problem :)