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:

#include <stdio.h>

#define MAX_SIZE 100

int queue[MAX_SIZE];
int front = -1, back = -1;

// Function to insert an element into the queue
void enqueue(int item) {
    if (back == MAX_SIZE - 1) {
        printf("Error: Queue is full\n");
        return;
    }
    if (front == -1) {
        front = 0;
    }
    back++;
    queue[back] = item;
}

// Function to remove an element from a queue
int dequeue() {
    if (front == -1 || front > back) {
        printf("Error: Queue is empty\n");
        return -1;
    }
    int item = queue[front];
    front++;
    return item;
}

// Function to find minimum value in the queue
int findMin() {
    if (front == -1 || front > back) {
        printf("Error: Queue is empty\n");
        return -1;
    }
    int min = queue[front];
    for (int i = front; i <= back; i++) {
        if (queue[i] < min) {
            min = queue[i];
        }
    }
    return min;
}


// Function to display the elements in the queue
void display() {
    printf("Queue elements are: ");
    for (int i = front; i <= back; i++) {
        printf("%d ", queue[i]);
    }
    printf("\n");
}

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 sum of the elements 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();
    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();
    min_val = findMin();
    printf("Minimum  value in the queue is: %d\n", min_val);
    return 0;;
}

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:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Find the maximum element in a queue.
Next: Delete the nth element of a queue.