4.4. Lab: String Operations

4.4.1. Goals for this lab:

  1. Explore some of the properties of the pre-defined String class.
  2. Write conditional statements.
  3. Think about problem solving.

This lab depends on the introductory material earlier in this chapter, particularly keep handy Summary of String Length and Some Instance Methods. Be mindful of the processes developed in class filling in A Creative Problem Solution.

Parts 2 and 4 also depend on Decisions through More Conditional Expressions.

Design, compile and run a single C# program to accomplish all of the following tasks. Add one part at a time and test before trying the next one. The program can just include a Main method, or it is neater to split things into separate methods (all static void, with names like ShowLength, SentenceType, LastFirst1, LastFirst), and have Main call all the ones you have written so far (or for testing purposes, just the one you are working on, with the other function calls commented out). Use the UIF class for user input. You can copy the file into your project.

Alternately practice using an Xamarin Studio library reference: Create a new project in a solution in which you already have added the ui library project. Make the ui project be a reference for the lab project.

Make sure your program has namespace IntroCS; to match the ui project. Beware of modifying the sample Program.cs generated by Xamarin Studio - it will use the project name for a namespace. We are never going to use that.

  1. Read a string from the keyboard and print the length of the string, with a label.

  2. Read a sentence (string) from a line of input, and print whether it represents a declarative sentence (i.e. ending in a period), interrogatory sentence (ending in a question mark), or an exclamation (ending in exclamation point) or is not a sentence (anything else).

    This may be the first time you write a conditional statement. (This needs the next chapter.) It makes sense to only make small changes at once and build up to final code. First you might just code it to check if a sentence is declarative or not. Then remember you can test further cases with else if (...).

  3. Read a whole name from a single line of user input. Do not ask for first and last names to be entered on separate lines! Assume first and last names are separated by a space (no middle name). Print last name first followed by a comma and a space, followed by the first name. For example, if the input is "Marcel Proust", the output is "Proust, Marcel".

  4. Improve the previous part, so it also allows a single name without spaces, like “Socrates”, and prints the original without change. If there are two parts of the name, it should work as in the original version. (This needs syntax from the next chapter.)

Run the program (with parts 1, 2 and 4 active) from a terminal window and show your TA when you are done. You should run it twice to show off both paths through part 4. Alternately have the main program just call part 4 twice!