vector.cpp

#include<bits/stdc++.h>
using namespace std;
//vector is used to store the elements in a linear fashion,when we dont want to store the elements in a distorted  order
int main()
{

    vector<int> arr;
    // cout<<arr.size();
    // cout<<arr.capacity()<<endl;
    // arr.push_back(1);
    // cout<<arr.size();
    // cout<<arr.capacity()<<endl;
    // arr.push_back(2);
    // cout<<arr.size();
    // cout<<arr.capacity()<<endl;
    // arr.push_back(3);
    // cout<<arr.size();
    // cout<<arr.capacity()<<endl;

    // vector<int> yash;
    // yash.push_back(1);//instead of push_back() we can also use emplace_back(); as it is slightly faster than push back
    // yash.push_back(5);
    // yash.push_back(6);
    // yash.push_back(4);
    // yash.push_back(2);
    // yash.push_back(3);
    // for(auto it=yash.begin();it!=yash.end();it++)
    // {
    //     cout <<*it<<" ";//it is not a variable its iterator hence we didnt used yash.at(it)
    // }
    // cout<<endl;
    
//     vector<int> dev(yash);
//     //or
//     //vector<int> dev(yash.begin(),yash.end());  //works as [ ) first included and last not included
//     for(auto it:dev)
//     {
//         cout <<it<<" ";
//     }
//     cout<<endl;


//     swap(yash,arr);     //used for swapping places

//     for(auto it:yash)
//     {
//         cout<<it<<" ";
//     }
//     cout<<endl;


//     //defining 2d vector
//     vector<vector<int>> vec;
//     vec.push_back(yash);
//     vec.push_back(arr);


    //defining a 10x20 vector
//     vector<vector<int>> vctr(1,vector<int>(2,10));
//     vctr.push_back(vector<int>(2,4)); 
//     for(auto it:vctr){   //iterating 2d vector
//    for(auto col:it){  
//       cout <<col<<endl;
//         }
//     }
//     cout<<endl;
    



    return 0;
}