﻿ C - Find the minimum element in a queue

# C Exercises: Find the minimum element in a queue

## C Queue: Exercise-10 with Solution

Write a C program to find the minimum element in a queue.

Sample Solution:

C Code:

``````// Header file inclusion for standard input and output operations
#include <stdio.h>
#define MAX_SIZE 100

int queue[MAX_SIZE]; // Array to store elements of the queue
int front = -1, back = -1; // Initialize front and back pointers

// Function to insert an element into the queue
void enqueue(int item) {
if (back == MAX_SIZE - 1) { // Check if the queue is full
printf("Error: Queue is full\n"); // Print error message if the queue is full
return;
}
if (front == -1) { // Check if the queue is empty
front = 0; // If empty, set front to 0
}
back++; // Increment the back pointer
queue[back] = item; // Add the item to the queue
}

// Function to remove an element from a queue
int dequeue() {
if (front == -1 || front > back) { // Check if the queue is empty
printf("Error: Queue is empty\n"); // Print error message if the queue is empty
return -1; // Return -1 to indicate an empty queue
}
int item = queue[front]; // Get the front element of the queue
front++; // Move the front pointer to the next element
return item; // Return the removed element
}

// Function to find the minimum value in the queue
int findMin() {
if (front == -1 || front > back) { // Check if the queue is empty
printf("Error: Queue is empty\n"); // Print error message if the queue is empty
return -1; // Return -1 to indicate an empty queue
}
int min = queue[front]; // Initialize min with the first element of the queue
// Loop through the elements of the queue to find the minimum value
for (int i = front; i <= back; i++) {
if (queue[i] < min) { // Compare the current element with min
min = queue[i]; // Update min if the current element is smaller
}
}
return min; // Return the minimum value
}

// Function to display the elements in the queue
void display() {
printf("Queue elements are: "); // Print message to indicate queue elements
for (int i = front; i <= back; i++) { // Loop through the elements of the queue
printf("%d ", queue[i]); // Print the current element
}
printf("\n"); // Print a newline after displaying all elements
}

int main() {
// Insert some elements into the queue.
enqueue(1);
enqueue(2);
enqueue(3);
enqueue(4);
enqueue(5);
// Display the elements in the queue.
display();
// Find the minimum value in the queue.
int min_val = findMin();
printf("Minimum value in the queue is: %d\n", min_val);
printf("\nRemove 2 elements from the said queue:\n");
dequeue();
dequeue();
// Display the elements in the queue.
display();
// Recalculate the minimum value in the queue.
min_val = findMin();
printf("Minimum value in the queue is: %d\n", min_val);
printf("\nInsert 3 more elements:\n");
enqueue(600);
enqueue(-427);
enqueue(519);
// Display the elements in the queue.
display();
// Recalculate the minimum value in the queue.
min_val = findMin();
printf("Minimum value in the queue is: %d\n", min_val);
return 0; // Return 0 to indicate successful execution
}
```
```

Sample Output:

```Queue elements are: 1 2 3 4 5
Minimum value in the queue is: 1

Remove 2 elements from the said queue:
Queue elements are: 3 4 5
Minimum value in the queue is: 3

Insert 3 more elements:
Queue elements are: 3 4 5 600 -427 519
Minimum  value in the queue is: -427
```

Flowchart:

C Programming Code Editor:

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