Merge pull request #146 from kartikeysingh6/master

Added Circular Queue in C++ DS

Author: larissalages

data_structures/C++/circular_queue.cpp

@@ -0,0 +1,62 @@
+#include<iostream>
+using namespace std;
+int f=-1;
+int r=-1;
+int N=3;
+int Q[3];
+
+void Enq(){int x;
+	if((f==0 && r==N-1) || f-r==1){
+		cout<<"Queue if Full!"<<endl;
+		return;
+	}
+	cout<<"Enter element to insert: ";
+	cin>>x;
+	r=(r+1)%N;
+	Q[r]=x;
+	if(f==-1)
+		f=0;
+}
+
+void Deq(){
+	if(f==-1){
+		cout<<"Queue is Empty!"<<endl;
+		return;
+	}
+	if(f==r){
+		cout<<"Removed element is "<<Q[f];
+		f=r=-1;
+		return;
+	}
+	cout<<"Removed element is "<<Q[f];
+	f=(f+1)%N;
+}
+
+void Peek(){
+	if(f==-1){
+		cout<<"Queue is Empty!"<<endl;
+		return;
+	}
+	cout<<"Front: "<<Q[f];
+	cout<<" Rear: "<<Q[r]<<endl;
+}
+
+int main(){int n=0;
+	while(n!=4){
+		cout<<endl<<"1.Enqueue"<<endl<<"2.Dequeue"<<endl<<"3.Peek"<<endl<<"4.Exit"<<endl;
+		cout<<"Enter choice: ";
+		cin>>n;
+		cout<<endl;
+		switch(n){
+			case 1:	Enq();
+					break;
+			case 2: Deq();
+					break;
+			case 3: Peek();
+					break;
+			case 4: return 0;
+			default: break;
+		}
+	}	
+	return 0;
+}