Implement a Circular Queue as an Array - C Data Structure

C examples for Data Structure:Queue

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Description

Implement a Circular Queue as an Array

Demo Code

#include <stdio.h>
#define SIZE 8/*from  ww w  .  j ava2 s  .  c o  m*/

int circQue[SIZE];
int frontCell = 0;
int rearCell = 0;
int count = 0;

void insertCircQue()
{
   int num;
   if (count == SIZE) {
      printf("\nCircular Queue is Full. Enter Any Choice Except 1.\n ");
   }
   else {
      printf("\nEnter data, i.e, a number N (0 <= N : 30000): ");
      scanf("%d", &num);
      circQue[rearCell] = num;
      rearCell = (rearCell + 1) % SIZE;
      count++;
      printf("\nData Inserted in the Circular Queue. \n");
   }
}

void deleteCircQue()
{
   if (count == 0) {
      printf("\nCircular Queue is Exhausted!\n");
   }
   else {
      printf("\nElement Deleted from Cir Queue is %d \n",
         circQue[frontCell]);
      frontCell = (frontCell + 1) % SIZE;
      count--;
   }
}

void displayCircQue()
{
   int i, j;
   if (count == 0) {
      printf("\nCircular Queue is Exhausted!\n ");
   }
   else {
      printf("\nElements in Circular Queue are given below: \n");
      j = count;
      for (i = frontCell; j != 0; j--) {
         printf("%d   ", circQue[i]);
         i = (i + 1) % SIZE;
      }
      printf("\n");
   }
}
int displayMenu()
{
   int choice;
   printf("\nEnter 1 to Insert Data.");
   printf("\nEnter 2 to Delete Data.");
   printf("\nEnter 3 to Display Data.");
   printf("\nEnter 4 to Quit the Program. ");
   printf("\nEnter Your Choice: ");
   scanf("%d", &choice);
   return choice;
}

int main()
{
   int choice;
   do {                              /* do-while loop begins. */
      choice = displayMenu();
      switch (choice) {                /* switch statement begins. */
      case 1:
         insertCircQue();
         break;
      case 2:
         deleteCircQue();
         break;
      case 3:
         displayCircQue();
         break;
      case 4:
         return(0);
      default:
         printf("\nInvalid Choice. Please enter again. \n ");
      }                               /* switch statement ends. */
   } while (1);                       /* do-while loop ends. */
}

Result


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