TheAlgorithms-C-Plus-Plus/hashing/chaining.cpp

#include <math.h>
#include <iostream>
using namespace std;

struct Node {
    int data;
    struct Node *next;
} * head[100], *curr;

void init() {
    for (int i = 0; i < 100; i++) head[i] = NULL;
}

void add(int x, int h) {
    struct Node *temp = new Node;
    temp->data = x;
    temp->next = NULL;
    if (!head[h]) {
        head[h] = temp;
        curr = head[h];
    } else {
        curr = head[h];
        while (curr->next) curr = curr->next;
        curr->next = temp;
    }
}

void display(int mod) {
    struct Node *temp;
    int i;
    for (i = 0; i < mod; i++) {
        if (!head[i]) {
            cout << "Key " << i << " is empty" << endl;
        } else {
            cout << "Key " << i << " has values = ";
            temp = head[i];
            while (temp->next) {
                cout << temp->data << " ";
                temp = temp->next;
            }
            cout << temp->data;
            cout << endl;
        }
    }
}

int hash(int x, int mod) { return x % mod; }

void find(int x, int h) {
    struct Node *temp = head[h];
    if (!head[h]) {
        cout << "Element not found";
        return;
    }
    while (temp->data != x && temp->next) temp = temp->next;
    if (temp->next)
        cout << "Element found";
    else {
        if (temp->data == x)
            cout << "Element found";
        else
            cout << "Element not found";
    }
}

int main(void) {
    init();
    int c, x, mod, h;
    cout << "Enter the size of Hash Table. = ";
    cin >> mod;
    bool loop = true;
    while (loop) {
        cout << endl;
        cout << "PLEASE CHOOSE -" << endl;
        cout << "1. Add element." << endl;
        cout << "2. Find element." << endl;
        cout << "3. Generate Hash." << endl;
        cout << "4. Display Hash table." << endl;
        cout << "5. Exit." << endl;
        cin >> c;
        switch (c) {
        case 1:
            cout << "Enter element to add = ";
            cin >> x;
            h = hash(x, mod);
            h = fabs(h);
            add(x, h);
            break;
        case 2:
            cout << "Enter element to search = ";
            cin >> x;
            h = hash(x, mod);
            find(x, h);
            break;
        case 3:
            cout << "Enter element to generate hash = ";
            cin >> x;
            cout << "Hash of " << x << " is = " << hash(x, mod);
            break;
        case 4:
            display(mod);
            break;
        default:
            loop = false;
            break;
        }
        cout << endl;
    }
    /*add(1,&head1);
    add(2,&head1);
    add(3,&head2);
    add(5,&head1);
    display(&head1);
    display(&head2);*/
    return 0;
}