Write in C++

3. Give the function definition for the function with the following function declaration. Embed your definition in a suitable test program. void get_double(double& input_number); //Postcondition: input_number is given a value //that the user approves of. You can assume that the user types in the input in normal everyday notation, such as 23.789, and does not use e-notation to type in the number. Model your definition after the definition of the function get int given in Display 8.3 so that your function reads the input as characters, edits the string of characters, and converts the resulting string to a number of type double. You will need to define a function like CHAPTER 8/ Strings and Vectors read_and_clean that is more sophisticated than the one in Display 8.2, since it must cope with the decimal point. This is a fairly easy project. For a more difficult project, allow the user to enter the number in either the normal everyday notation, as discussed above, or in e-notation. Your function should decide whether or not the input is in e-notation by reading the input, not by asking the user whether she or he will use e-notation