Queue Implementation Using Array C Program

#include<stdio.h> #define MAXSIZE 5 void enqueue(); int dequeue(); void peek(); int isEmpty(); int isFull(); int queue[MAXSIZE]; int rear = -1, front = -1; void main() { int value, choice; while(1) { printf("Enter choice.\n1. Push\n2. Pop\n3. Display\n4. Exit\n"); scanf("%d",&choice); switch(choice) { case 1: if(isFull()) { printf("Cannot push. Overflow.\n"); break; } printf("Enter number\n"); scanf("%d",&value); enqueue(value); break; case 2: if(isEmpty()) { printf("Cannot pop. Underflow.\n"); break; } value = dequeue(); printf("Value popped = %d\n",value); break; case 3: peek(); break; case 4: return; } } } int isFull() { if(rear == MAXSIZE-1) return 1; return 0; } int isEmpty() { if(front == -1 || front > rear) return 1; return 0; } void enqueue(int value) { queue[++rear] = value; if(front == -1) front++; } int dequeue() { int value = queue[front++]; return value; } void peek() { int i; for(i=front;i<=rear;i++) printf("%d ",queue[i]); printf("\n"); }

Queue using array in C