C++ STL Vector Examples of Various Common Functions

stl_vector.cpp

#include<bits/stdc++.h>
using namespace std; 

int main()
{
	/* Basic Declaration */ 
	// vector<int> vec_1(5); 
	// vector<int> vec_2(4,10); 
	// vector<int> vec_3{1,2,3,4,5};

	// vector<int> vec_4; 
	// vec_4.push_back(10); 

	// int N,M;
	// cin>>N;
	// vector<int> vec_5; 
	// for(int i=0;i<N;i++){
	// 	cin>>M;
	// 	vec_5.push_back(M);
	// }

	/* How to Access Vector Elements */ 
	// vector<int> vec(10);
	// cout<<vec[0];
	// for(int i=0;i<vec.size;i++){
	// 	cout<<vec[i];
	// }
	// cout<<vec.front()<<endl;
	// cout<<vec.back()<<endl; 

	/* How to copy elements from one vector to another */
	// vector<int> vec_1{1,2,3,4,5};
	// vector<int> vec_2(vec_1);

	/* How to insert elements in Vector */ 

	// vector<int> vec_1{1,2,3,4,5};
	// vec_1.insert(vec_1.begin(),30);
	// vec_1.inser(vec_1.begin(),3,10);
	// vec_1.insert(vec_1.begin(),{1,2,3,4});
	// vector<int> vec_2;
	// vec_1.insert(vec_1.begin(),vec_2.begin(),vec_2.end());

	/* Erase Elements from the Vector */

	// vector<int> vec_1{10,20,30,40,50};

	// vec_1.erase(vec_1.begin(),vec_1.begin()+2);
	// vec_1.pop_back();
	
	/* Reverse a vector */ 
	//reverse(vec_1.begin(), vec_1.end()); 

	/* How to search on Vectors */ 
	// vector<int> vec_1 { 10, 20, 30, 40 };
	// auto it = find(vec_1.begin(),vec_1.end(),21);
	// int position = it-vec_1.begin();

	/* Find if a Vector exist in another vector or not */ 
	// vector<int> v1 = { 1, 2, 3, 4, 5, 6, 7 }; 
 //  	vector<int> v2 = { 3, 4, 5 }; 
 //  	auto i1 = std::search(v1.begin(), v1.end(), v2.begin(), v2.end()); 
 //    // checking if iterator i1 contains end pointer of v1 or not 
 //    if (i1 != v1.end()) { 
 //        cout << "vector2 is present at index " << (i1 - v1.begin()); 
 //    } else { 
 //        cout << "vector2 is not present in vector1"; 
 //    } 


    /* Binary Search on C++ STL */
	vector<int> v1 = { 1, 2, 3, 4, 5, 6, 7 }; 
    int pos = binary_search(arr.begin(), arr.end(), 15)
	cout<<pos<<endl; // If exist will return 1 

	
	/* Checking Upper or lower bound. It means checking the first and last occurance of a particular value */ 
	vector<int> v1 = { 1, 2, 3, 4, 5, 6, 7 }; 
 //    auto low_pos  = lower_bound(v1.begin(),v1.end(),3);
	// auto upr_pos  = upper_bound(v1.begin(),v1.end(),3);
    
 //    cout<< low_pos-v1.begin()<<endl;	 
 //    cout<< upr_pos-v1.begin()<<endl;


    /* Sort a Vector */ 
    // vector<int> vec_1 ={10,2,41,15};

    // // Ascending Order 
    // sort(vec_1.begin(),vec_2.end());

    // //Descending Order 
    // sort(vec_1.begin(),vec_2.end(),greater<int>());

}