1,. (20 points) Display a message for asking your first name, and then use your first name display a greeting message, e.g. "Hello, John!" 2. (30 points) Write a program to calculate the sum from 20 tol. Use while loop to do the calculation. 3. (20 points) Write a complete C++ program that asks the user to enter the necessary information about the cube, calculate the volume in a function (named as calculate vol, using pointer to pass the volume value out), then display the cube volume in main function. The volume of cube is Vol Cube d Where d is the length. 4. (30 points) Declare a vector container. Using keyboard to input several floating point numbers, say at least five floating point numbers; find the biggest number and display the result