I need help on forming the code in C$++.$ Keep getting errors and would love some help.

Goal: Learn how to read and store values from standard input.

Assignment: Write some code $($not a complete program$)$ that declares three double variables and reads three double values from the input and prints out their weighted average. The first number has a weight of $1,$ the second of $2,$ and the third of $3.$

Sample Run $($User input inside

$7\mathrm{.}0$