# hashing code

# ✅ 1️⃣ Open Hashing (Separate Chaining)

👉 `list` use ki  
👉 **insert + delete + display**  
👉 sab **functions**, call from `main()`

```plaintext
#include <iostream>
#include <list>
using namespace std;

#define SIZE 5

// INSERT
void insertOpen(list<int> table[], int key) {
    int index = key % SIZE;
    table[index].push_back(key);
}

// DELETE
void deleteOpen(list<int> table[], int key) {
    int index = key % SIZE;
    table[index].remove(key);
}

// DISPLAY
void displayOpen(list<int> table[]) {
    for (int i = 0; i < SIZE; i++) {
        cout << i << " : ";
        for (int x : table[i])
            cout << x << " -> ";
        cout << "NULL\n";
    }
}

int main() {
    list<int> table[SIZE];

    insertOpen(table, 10);
    insertOpen(table, 15);
    insertOpen(table, 20);

    deleteOpen(table, 15);

    displayOpen(table);
}
```

---

# ✅ 2️⃣ Linear Probing (Closed Hashing)

👉 array only  
👉 **tombstone delete**  
👉 sab **functions**

```plaintext
#include <iostream>
using namespace std;

#define SIZE 7
#define EMPTY -1
#define DELETED -2

void init(int table[]) {
    for (int i = 0; i < SIZE; i++)
        table[i] = EMPTY;
}

// INSERT
void insertLinear(int table[], int key) {
    int index = key % SIZE;
    while (table[index] != EMPTY && table[index] != DELETED)
        index = (index + 1) % SIZE;
    table[index] = key;
}

// DELETE
void deleteLinear(int table[], int key) {
    int index = key % SIZE;
    while (table[index] != EMPTY) {
        if (table[index] == key) {
            table[index] = DELETED;
            return;
        }
        index = (index + 1) % SIZE;
    }
}

// DISPLAY
void display(int table[]) {
    for (int i = 0; i < SIZE; i++)
        cout << i << " : " << table[i] << endl;
}

int main() {
    int table[SIZE];
    init(table);

    insertLinear(table, 10);
    insertLinear(table, 17);
    insertLinear(table, 24);

    deleteLinear(table, 17);

    display(table);
}
```

---

# ✅ 3️⃣ Quadratic Probing (Closed Hashing)

👉 **\+ i² jump**  
👉 **functions only**

```plaintext
#include <iostream>
using namespace std;

#define SIZE 7
#define EMPTY -1
#define DELETED -2

void init(int table[]) {
    for (int i = 0; i < SIZE; i++)
        table[i] = EMPTY;
}

// INSERT
void insertQuadratic(int table[], int key) {
    int index = key % SIZE;

    for (int i = 0; i < SIZE; i++) {
        int newIndex = (index + i*i) % SIZE;
        if (table[newIndex] == EMPTY || table[newIndex] == DELETED) {
            table[newIndex] = key;
            return;
        }
    }
}

// DELETE
void deleteQuadratic(int table[], int key) {
    int index = key % SIZE;

    for (int i = 0; i < SIZE; i++) {
        int newIndex = (index + i*i) % SIZE;
        if (table[newIndex] == EMPTY)
            return;
        if (table[newIndex] == key) {
            table[newIndex] = DELETED;
            return;
        }
    }
}

// DISPLAY
void display(int table[]) {
    for (int i = 0; i < SIZE; i++)
        cout << i << " : " << table[i] << endl;
}

int main() {
    int table[SIZE];
    init(table);

    insertQuadratic(table, 10);
    insertQuadratic(table, 17);
    insertQuadratic(table, 24);

    deleteQuadratic(table, 17);

    display(table);
}
```