Please identify and explain the key expressions used in the code below to calculate the value of mpg.

#include

using namespace std;

int main() { //declaring variables double miles; double gallons; float mpg;

//Prints Enter miles on screen cout << "Enter miles:"; //Stores integer given user input cin >> miles; //Prints Enter gallons on screen cout << "Enter gallons:"; //Stores integer given user input cin >> gallons; //Display mileage mpg = (float)miles / gallons; //Prints Miles per gallons on screen and flush stream cout << "Miles per gallons:" << mpg << endl; //Terminate the program return 0; }