17.Ex1 QueryVector.cpp

#include <vector>
#include <iostream>

using namespace std;

char DisplayOptions()
{
   cout << "What would you like to do?" << endl;
   cout << "Select 1: To enter an integer" << endl;
   cout << "Select 2: Query a value given an index" << endl;
   cout << "Select 3: To display the vector" << endl;
   cout << "Select 4: To quit!" << endl << "> ";

   char ch;
   cin >> ch;

   return ch;
}

int main()
{
   vector <int> vecData;

   char chUserChoice = '\0';
   while((chUserChoice = DisplayOptions()) != '4')
   {
      if(chUserChoice == '1')
      {
         cout << "Please enter an integer to be inserted: ";
         int nDataInput = 0;
         cin >> nDataInput;

         vecData.push_back(nDataInput);
      }
      else if(chUserChoice == '2')
      {
         cout << "Please enter an index between 0 and ";
         cout << (vecData.size() - 1) << ": ";
         size_t index = 0;
         cin >> index;

         if(index < (vecData.size()))
         {
            cout << "Element [" << index << "] = " << vecData[index];
            cout << endl;
         }
      }
      else if(chUserChoice == '3')
      {
         cout << "The contents of the vector are: ";
         for(size_t index = 0; index < vecData.size(); ++index)
            cout << vecData[index] << ' ';
         cout << endl;
      }
   }
   return 0;
}