Average of 5 Number using vector in c++

#include <iostream>
#include <vector>
using namespace std;

int main()

{
    vector<int> grades;   //declaration of vector
    int grade, total;
    double average;
    total = 0;
   
    for(int i=1; i<=5; ++i)        //Taking the input from user

    {
        cout << "Enter a grade: ";
        cin >> grade;
        grades.push_back(grade);
    }
   
    for(int i = 0; i < grades.size(); ++i)

    {
        //cout << grades[i] << " ";
        total += grades[i];
    }
    

    average = total / grades.size();
    cout << "the average is " << average << endl;
    

    return 0;
}

OUTPUT:

A vector<int> (meaning 'a vector of ints') in much the same way as you would use an ordinary C array, except that vector eliminates the chore of managing dynamic memory allocation by hand.

vector<int> v(3); // Declare a vector (of size 3 initially) of ints
     v[0] = 7;
     v[1] = v[0] + 3;
     v[2] = v[0] + v[1]; // v[0] == 7, v[1] == 10, v[2] == 17
     v.push_back(13); // add another element - the vector has to expand

Note the use of the push_back function - adding elements this way will make the container expand.

Remember that:
1. vector elements can move! insert, for instance, changes its 1st argument.
2. vector doesn't have arithmetic operations: valarray (which is described
later) does. p.51
3. vector doesn't have range-checking by default.