c - My Circular Queue implementation is not working properly -

i have created program implement circular queue insert, delete , display. insertion working fine , deletion once try enter numbers after deletion, nothing displayed. here source code:

#include<stdio.h> #include<conio.h> #define size 5 int front = -1; int rear = -1; int queue[size]; void enqueue(int item); int dequeue(); void display(); void main() {     int item, choice, cont = 1;     clrscr();      while(cont == 1)     {         printf("\n1.enqueue queue.\n");         printf("\n2.dequeue queue.\n");       printf("\n3.display quesue elements\n");          printf("\nenter choice: ");         scanf("%d",&choice);          switch(choice)         {             case 1:                 printf("\nenter value of item: ");                 scanf("%d",&item);                 enqueue(item);                 break;              case 2:                 item = dequeue();                 if(item != null)                 {                     printf("\nitem dequeued: %d\n",item);                 }                 break;          case 3:                 display();                 break;              default:                 printf("\ninvalid choice.\n");                 break;         }          printf("\ndo want continue (1/0): ");         scanf("%d",&cont);     }      getch(); }   void enqueue(int item) {    if(front==0 && rear==size-1)     printf("\n queue overflow occured");   else if(front==-1 && rear==-1)   {       front=rear=0;       queue[rear]=item;    }   else if(rear==size-1 && front!=0)   {     rear=0;     queue[rear]=item;   }     else    {       rear++;       queue[rear]=item;    }   } int dequeue() {     int item = null;     if(front == -1 && rear == -1)     {         printf("\nqueue empty. dequeue not possible.\n");     }     else     {         item = queue[front];         queue[front] = null;          if(front == rear)         {             front = -1;             rear = -1;         }         else         {             front = front + 1;         }     }     return(item); } void display() {     int i;     if(front==-1)       printf("\n no elements display");     else     {       printf("\n queue elements are:\n ");       for(i=front;i<=rear;i++)       {           printf("\t %d",queue[i]);       }     } } 

check code working fine.

few suggestions don't use conio.h [clrscr(), , getch()] these not standards.

try code below worked me fine.

code

    #include<stdio.h>     #define size 5     int front = -1;     int rear = -1;     int queue[size];     void enqueue(int item);     int dequeue();     void display();     int main()     {         int item, choice, cont = 1;          while(cont == 1)         {             printf("\n1.enqueue queue.\n");             printf("\n2.dequeue queue.\n");           printf("\n3.display quesue elements\n");              printf("\nenter choice: ");             scanf("%d",&choice);              switch(choice)             {                 case 1:                     printf("\nenter value of item: ");                     scanf("%d",&item);                     enqueue(item);                     break;                  case 2:                     item = dequeue();                     if(item != null)                     {                         printf("\nitem dequeued: %d\n",item);                     }                     break;              case 3:                     display();                     break;                  default:                     printf("\ninvalid choice.\n");                     break;             }              printf("\ndo want continue (1/0): ");             scanf("%d",&cont);         }          printf("");         return 0;     }       void enqueue(int item)     {        if(front==0 && rear==size-1)         printf("\n queue overflow occured");       else if(front==-1 && rear==-1)       {           front=rear=0;           queue[rear]=item;        }       else if(rear==size-1 && front!=0)       {         rear=0;         queue[rear]=item;       }         else        {           rear++;           queue[rear]=item;        }       }     int dequeue()     {         int item = null;         if(front == -1 && rear == -1)         {             printf("\nqueue empty. dequeue not possible.\n");         }         else         {             item = queue[front];             queue[front] = null;              if(front == rear)             {                 front = -1;                 rear = -1;             }             else             {                 front = front + 1;             }         }         return(item);     }     void display()     {         int i;         if(front==-1)           printf("\n no elements display");         else         {           printf("\n queue elements are:\n ");           for(i=front;i<=rear;i++)           {               printf("\t %d",queue[i]);           }         }      } 

output

    want continue (1/0): 1      1.enqueue queue.      2.dequeue queue.      3.display quesue elements      enter choice: 3       queue elements are:        5   5     want continue (1/0): 1      1.enqueue queue.      2.dequeue queue.      3.display quesue elements      enter choice: 1      enter value of item: 43      want continue (1/0): 1      1.enqueue queue.      2.dequeue queue.      3.display quesue elements      enter choice: 3       queue elements are:        5   5   43     want continue (1/0): 1      1.enqueue queue.      2.dequeue queue.      3.display quesue elements      enter choice: 2      item dequeued: 5      want continue (1/0): 1      1.enqueue queue.      2.dequeue queue.      3.display quesue elements      enter choice: 3       queue elements are:        5   43     want continue (1/0):