Pointing to the last element and ending of program

Been working on some C++ exercises and what I’m doing is finding out the 5 number summary(max, min, q1,q2,q3) and the number of inputted ints for a group of integers that are inputted. This is an extension of an exercise for Accelerated C++. There are a few things that I’m unsure of. Firstly how do to refer to the last element if I don’t know how many elements there are in the vector. It also shows the results once you input the ints that you want to have in and then end-of-file. How do you end-of-file in a program. I’ve tried pressing the end button but it doesn’t work. Also I have used one and two as the 1st and 3rd quartile respectively. Have I done the right thing, if not, why not and how would you do it. Thanks for the help.

Code:

#include<algorithm>
#include<iomanip>
#include<ios>
#include<iostream>
#include<string>
#include<vector>
using namespace std;

int main()
{
    cout<<"Please input your numbers:";
    vector<int> numbers;
    int number;
    while(cin>>number)
          numbers.push_back(number);
    typedef vector<int>::size_type numbersize;
   
    
    numbersize size=numbers.size();
    if(size==0){
                cout<<endl<<"You must enter your numbers"<<endl;
                return 1;
    }
    //sort the grades
    sort(numbers.begin(),numbers.end());
    
    //computer the median homework grade
    numbersize mid=size/2;
    double median;
    median= size % 2 ==0 ? (numbers[mid] +numbers[mid-1])/2
                         : numbers[mid];
                         
    numbersize one= mid/2;
    numbersize two=mid + one;
    
    cout<<"The median is: "<<median;
    cout<<"The 1st quartile is: "<< one;
    cout<<"The 3rd quartile is: "<<two;
    cout<<"The min value is: "<<numbers[0];
    cout<<"There are "<<numbers.size()<<" elements that you inputted";
}

> Firstly how do to refer to the last element if I don’t know how many elements there are in the vector
Your code already contains the answer - it's the .size()

> How do you end-of-file in a program
For DOS/Win32, press ctrl-z at the start of a line, then press enter (perhaps)
For Linux/Unix, it's usually ctrl-d

> Also I have used one and two as the 1st and 3rd quartile respectively. Have I done the right thing
If you're concerned about the calculation, then lookup statistics on http://mathworld.wolfram.com/

Your cout need endl

Originally Posted by Daniel Primed

How do you end-of-file in a program.

For the purposes of your program, stopping getting input from the user and inserting the integers into the vector, you could also just type in a non-numeric character(s) followed by <enter>. That would cause the while(cin>>number) part of the code to evaluate to false and break out of that loop.

Originally Posted by Salem

> Firstly how do to refer to the last element if I don’t know how many elements there are in the vector
Your code already contains the answer - it's the .size()

size() would tell you how many elements you have. To refer to the last element of a vector use back().