vector data structure and readme.md updated in c++ (#790)

C-Plus-Plus/README.md

@@ -371,6 +371,7 @@ Format: -[Program name](name of the file)
 - [Tim sort](Tim_Sort.cpp)
 - [Twin prime](twin_prime.cpp)
 - [Value of Pi by Random Numbers](ValueOfPi.cpp)
+- [vector data structure](vector.cpp)
 - [Word Break](Word-Break.cpp)
 - [BFS with path](BFS.cpp)
 - [Longest Path in DAG](Longest_path_in_DAG.cpp)

C-Plus-Plus/vector.cpp

@@ -0,0 +1,76 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+using namespace std;
+/*Vectors are same as dynamic arrays with the ability to resize itself 
+automatically when an element is inserted or deleted*/
+void iterate_over_vector(auto start,auto end)
+{
+	for(auto i=start;i!=end;i++)
+	{
+		cout<<*i<<" ";
+	}
+	cout<<endl;
+}
+void insert_element(vector <int> &test,auto pos,int value)
+{
+	// O(n+m)
+	test.insert(pos,value);  
+}
+void erase_element(vector <int> &test,auto pos)
+{
+	//  O(n)
+	test.erase(pos);  
+}
+
+bool is_vector_empty(vector <int> &test)
+{
+	return test.empty();
+}
+
+int main()
+{
+	vector <int> test;
+	test.push_back(5);              // 	add 5 at the end    O(1)
+	test.push_back(4);              // 	added 4 after 5      O(1)
+	test.push_back(8);              //	Vector elements are placed in contiguous storage.
+	test.push_back(1);				//	O(1)							
+	/*   Iterate over vector
+		begin() – Returns an iterator pointing to the first element in the vector
+		end() – Returns an iterator pointing to the theoretical element that follows the last element in the vector  */
+
+	cout<<"Initial vector: ";
+	iterate_over_vector(test.begin(),test.end());        
+	cout<<"Size of vector: "<<test.size()<<endl;
+
+	insert_element(test,test.begin()+2,5);              //insert element at given iterator	
+	cout<<"vector after insertion: ";                  	
+	iterate_over_vector(test.begin(),test.end());
+	cout<<"Size of vector: "<<test.size()<<endl;
+	test.pop_back();                                    //delete last element
+	erase_element(test,test.begin()+1);                 //erase element at given iterator
+
+	cout<<"vector after erasing some elements: ";
+	iterate_over_vector(test.begin(),test.end());
+	cout<<"Size of vector: "<<test.size()<<endl;
+	cout<<"Is vector empty: "<<is_vector_empty(test)<<endl;
+
+ 	test.clear();                       // remove all the elements of the vector container
+
+ 	cout<<"Is vector empty: "<<is_vector_empty(test)<<endl;
+
+	return 0;
+}
+
+/*
+output:
+
+Initial vector: 5 4 8 1
+Size of vector: 4 
+vector after insertion: 5 4 5 8 1
+Size of vector: 5
+vector after erasing some elements: 5 5 8
+Size of vector: 3
+Is vector empty: 0
+Is vector empty: 1 
+*/