std::vector — Dynamic Arrays

The Most Useful Container in C++

#include <vector>

vector<int> v = {1, 2, 3};
v.push_back(4);          // {1,2,3,4}
v.pop_back();            // {1,2,3}
v.size()                 // 3
v[1]                     // 2
v.front()                // 1
v.back()                 // 3
v.empty()                // false
v.clear()                // empty vector {}

Other initializations

vector<int> a(5, 0);     // 5 zeros: {0,0,0,0,0}
vector<int> b(a);        // copy of a

Range-based for

for (int x : v)          { cout << x; }  // by value
for (const int& x : v)  { cout << x; }  // by const ref (no copy)
for (int& x : v)        { x *= 2; }     // by ref (can modify)

Your Task

Write vectorSum(vector<int> v) and vectorAvg(vector<int> v) that return the sum and average (as double) of all elements.