Notes

#include <iostream>
using namespace std;
int queue[100], n = 100, front = - 1, rear = - 1;
void In() {
int value;
if (rear == n - 1)
cout<<"Queue Overflow"<<endl;
else {
if (front == - 1)
front = 0;
cout<<"Insert the element in queue : "<<endl;
cin>>value;
rear++;
queue[rear] = value;
}
}
void De() {
if (front == - 1 || front > rear) {
cout<<"Queue Underflow ";
return ;
} else {
cout<<"Element deleted from queue is : "<< queue[front] <<endl;
front++;;
}
}
void Di() {
if (front == - 1)
cout<<"Queue is empty"<<endl;
else {
cout<<"Queue elements are : ";
for (int i = front; i <= rear; i++)
cout<<queue[i]<<" ";
cout<<endl;
}
}
int main() {
int ch;
cout<<"1) Insert element "<<endl;
cout<<"2) Delete element "<<endl;
cout<<"3) Display all the elements "<<endl;
cout<<"4) Exit"<<endl;
do {
cout<<"Enter your choice : "<<endl;
cin>>ch;
switch (ch) {
case 1: In();
break;
case 2: De();
break;
case 3: Di();
break;
case 4: cout<<"Exit"<<endl;
break;
default: cout<<"Invalid choice"<<endl;
}
}
while(ch!=4);

return 0;
}