Queue Implementation Using Functions in C

About this program

This is an example program in c queue programs. Read the concept first: C Array, then study the code and output below.

Definition

In each of the cases, the customer or object at the front of the line was the first one to enter, while at the end of the line is the last to have entered. Every time a customer finishes paying for their items (or a person steps off the escalator, or the machine part is removed from the assembly line, etc.) that object leaves the queue from the front. This represents the queue ?dequeue? function. Every time another object or customer enters the line to wait, they join the end of the line and represent the ?enqueue? function. The queue ?size? function would return the length of the line, and the ?empty? function would return true only if there was nothing in the line.

Simple Queue Program using functions

/* Simple Queue Program Using Functions in C*/
/* Data Structure Programs,C Array Examples */

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>

#define MAX_SIZE 100

int item, choice, i;
int arr_queue[MAX_SIZE];
int rear = 0;
int front = 0;
int exit_p = 1;

void insert() {
    if (rear == MAX_SIZE)
        printf("\n## Queue Reached Max!");
    else {
        printf("\nEnter The Value to be Insert : ");
        scanf("%d", &item);
        printf("\n## Position : %d , Insert Value  : %d ", rear + 1, item);
        arr_queue[rear++] = item;
    }
}

void removeData() {
    if (front == rear)
        printf("\n## Queue is Empty!");
    else {
        printf("\n## Position : %d , Remove Value  : %d ", front, arr_queue[front]);
        front++;
    }
}

void display() {
    printf("\n## Queue Size : %d ", rear);
    for (i = front; i < rear; i++)
        printf("\n## Position : %d , Value  : %d ", i, arr_queue[i]);
}

int main() {
    printf("\nSimple Queue Example - Array and Functions");
    do {
        printf("\n\n Queue Main Menu");

        printf("\n1.Insert \n2.Remove \n3.Display \nOthers to exit");
        printf("\nEnter Your Choice : ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                insert();
                break;
            case 2:
                removeData();
                break;
            case 3:
                display();
                break;
            default:
                exit_p = 0;
                break;
        }
    } while (exit_p);

    return 0;
}

Sample Output:

Simple Queue Example - Array and Functions

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 1

Enter The Value to be Insert : 100

## Position : 1 , Insert Value  : 100

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 1

Enter The Value to be Insert : 200

## Position : 2 , Insert Value  : 200

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 1

Enter The Value to be Insert : 300

## Position : 3 , Insert Value  : 300

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 1

Enter The Value to be Insert : 400

## Position : 4 , Insert Value  : 400

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 3

## Queue Size : 4
## Position : 0 , Value  : 100
## Position : 1 , Value  : 200
## Position : 2 , Value  : 300
## Position : 3 , Value  : 400

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 2

## Position : 0 , Remove Value  : 100

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 3

## Queue Size : 4
## Position : 1 , Value  : 200
## Position : 2 , Value  : 300
## Position : 3 , Value  : 400

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 2

## Position : 1 , Remove Value  : 200

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 3

## Queue Size : 4
## Position : 2 , Value  : 300
## Position : 3 , Value  : 400

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 1

Enter The Value to be Insert : 1100

## Position : 5 , Insert Value  : 1100

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 3

## Queue Size : 5
## Position : 2 , Value  : 300
## Position : 3 , Value  : 400
## Position : 4 , Value  : 1100

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 2

## Position : 2 , Remove Value  : 300

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 2

## Position : 3 , Remove Value  : 400

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 2

## Position : 4 , Remove Value  : 1100

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 2

## Queue is Empty!

 Queue Main Menu
1.Insert
2.Remove
3.Display
Others to exit
Enter Your Choice : 4

------------------
(program exited with code: 0)

Related Pages

Learn the concept first, then study the code:

• Data Structures — Browse all Data Structures.
• C Array — Concept — arrays and indices in queue logic.
• Simple Queue Program in C Programming — More in c queue programs.