Practice problems on vector in C++

 Practice Problems On Vector in C++

Hello, everyone in todays blog we are going to discuss the most interesting topic of C++ i.e. VECTOR. VECTOR is same as array just a little difference is that VECTOR can be resize but Arrays cannot be resize once it initialize .

Key Differences in VECTOR & Arrays

• Arrays are Static but VECTOR can be resize according to our need
• VECTORS and Arrays both stored in contiguous memory location.
• VECTORS some time also called as Dynamic Arrays

Basic Operations In VECTORS :

• Declaration

syntax:-vector<datatype>vector_name(size);

Ex:- vector<int>v;

• Size

v.size(); //by this function you can the length

• Resize

v.resize(new size); //by this you can resize your dynamic array

• Add Elements

v.push_back(element); //this will add element from last position

Ex:- 2 3 4

        v.push_back(5);

        2 3 4 5 //

• Insert Element

v.insert(position,element);

v.begin() // to find first element

v.end() // to find last element

• Delete Elements 

v.pop_back() //delete last element

Ex: 2 3 4

v.pop_back();

2 3 //final answer

• Delete All Elements Of Dynamic Array

v.clear();

These are all the functions used in Dynamic Arrays / VECTOR.

1.  

/*Write a C++ program to check whether numbers in

a vector can be rearranged so that each number

appears exactly once in a consecutive list of

numbers. Return true otherwise false.

Example:

1 2 5 0 3 6 7

Check consecutive numbers in the said vector! 0 */

#include<iostream>

#include<vector>

#include<algorithm>

using namespace std;

bool consecutive(vector<int>& v){

    sort(v.begin(),v.end());

    for(int i=0;i<v.size()-1;i++){

        if(v[i+1]-v[i]>1){

            return false;

        }

    }

    return true;

}

int main(){

    //declaring the vector

    vector<int>v={1,2,9,0,3,6,7};

        cout<<"Check consecutive numbers in the

said vector "<<consecutive(v)<<endl;

        return 0;

   

}

Output :-Check consecutive numbers in the said

vector 1

2.

/*Write a C++ program that returns the elements in

a vector that are strictly smaller than their

adjacent left and right neighbours.

Example:

Original Vector elements:

1 2 5 0 3 1 7

Vector elements that are smaller than its adjacent

neighbours:

0

1 */

#include<iostream>

using namespace std;

#include<bits/stdc++.h>

void smallerLeftRight(vector<int> &v){

    for(int i=1;i<v.size()-1;i++){

        if(v[i]<v[i-1] && v[i]<v[i+1]){

            cout<<v[i]<<endl;

        }

    }

    return ;

}

int main(){

    vector<int>v={1,2,5,0,3,1,7,4,6};

    smallerLeftRight(v);

    return 0;

}

Output :- 0

1

4

3.

/*Write a C++ program to create an n x n matrix by

taking an integer (n) as input from the user.

Example:

Input: 2

Input an integer value: Create an n x n matrix by

said integer:

2 2

2 2 */

#include<iostream>

#include<vector>

using namespace std;

int main(){

    int n;

    cout<<"Enter the size of the matrix"<<endl;

    cin>>n;

    vector<vector<int>>v(n,vector<int>(n));

    //input

   int input;

   cout<<"Enter the input"<<endl;

   cin>>input;

    //output

    for(int i=0;i<v.size();i++){

        for(int j=0;j<v.size();j++){

            cout<<(v[i][j]=input)<<" ";

        }

        cout<<endl;

    }

    return 0;

}

Output:-Enter the size of the matrix

4 Enter the input 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2