﻿ C++ Find the mode of all elements of a queue

# C++ Queue Exercises: Find the mode of all elements of a queue

## C++ Queue: Exercise-7 with Solution

Write a C++ program to find the mode of all elements of a queue.

Sample Solution:

C Code:

``````#include <iostream>
#include <map> // Include map library for using map data structure

using namespace std;

const int MAX_SIZE = 100;

class Queue {
private:
int front; // Front index of the queue
int rear; // Rear index of the queue
int arr[MAX_SIZE]; // Array to store elements

public:
Queue() {
front = -1; // Initialize front index to -1
rear = -1; // Initialize rear index to -1
}

bool isFull() {
return (rear == MAX_SIZE - 1); // Check if the queue is full
}

bool isEmpty() {
return (front == -1 && rear == -1); // Check if the queue is empty
}

void enqueue(int x) {
if (isFull()) {
cout << "Error: Queue is full" << endl; // Display error message if queue is full
return;
}
if (isEmpty()) {
front = 0;
rear = 0;
} else {
rear++;
}
arr[rear] = x; // Insert the element at the rear index
}

void dequeue() {
if (isEmpty()) {
cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
return;
}
if (front == rear) {
front = -1;
rear = -1;
} else {
front++;
}
}

int peek() {
if (isEmpty()) {
cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
return -1;
}
return arr[front]; // Return the element at the front of the queue
}

void display() {
if (isEmpty()) {
cout << "Error: Queue is empty" << endl; // Display error message if queue is empty
return;
}
cout << "Queue elements are: ";
for (int i = front; i <= rear; i++) {
cout << arr[i] << " "; // Display all elements in the queue
}
cout << endl;
}

int find_Mode() {
map < int, int > freq; // Map to store element frequency
int mode = -1; // Initialize mode to -1
int maxFreq = -1; // Initialize maximum frequency to -1
for (int i = front; i <= rear; i++) {
freq[arr[i]]++; // Increment frequency count for each element in the queue
if (freq[arr[i]] > maxFreq) {
maxFreq = freq[arr[i]]; // Update maximum frequency
mode = arr[i]; // Update mode to the element with maximum frequency
}
}
return mode; // Return the mode of the elements in the queue
}
};

int main() {
cout << "Initialize a Queue." << endl;
Queue q;
cout << "\nInsert some elements into the queue:" << endl;
q.enqueue(1);
q.enqueue(2);
q.enqueue(3);
q.enqueue(4);
q.enqueue(4);
q.display();

// Find and display the mode of elements in the queue
int mode_val = q.find_Mode();
cout << "Find the mode of all elements of the said queue: " << mode_val;

cout << "\n\nInput one more element into the queue:" << endl;
q.enqueue(3);
q.enqueue(3);
q.display();

// Find and display the mode of elements in the queue after adding new elements
mode_val = q.find_Mode();
cout << "Find the mode of all elements of the said queue: " << mode_val;

return 0;
}
```
```

Sample Output:

```Initialize a Queue.

Insert some elements into the queue:
Queue elements are: 1 2 3 4 4
Find the mode of all elements of the said queue: 4

Input one more element into the queue:
Queue elements are: 1 2 3 4 4 3 3
Find the mode of all elements of the said queue: 3
```

Flowchart:

CPP Code Editor: