Assignment 4 for CSCI 431: Ada

The gnat compiler for Ada has been installed on Burnsville. Here is a brief set of instructions for compiling a simple procedure or function (something that is not part of a package and does not use multiple tasks).

Programming Assignment

1. Part 1: Modifying a program
   • Copy table.adb to your directory, and look at the contents of the file until you understand what it is supposed to do.
   • Compile table.adb and look at the error messages. These messages contain four fields:
     1. The name of the file with the error
     2. The line number of the error
     3. A character position within that line
     4. A description of the error
     Some of the error messages are the result of syntax errors; you will have to fix those. The others (with the description, "invalid parameter list ..."), occur because the Text_IO package does not have a definition of the PUT() function that accepts INTEGER input. This can be fixed by using one of the generic child packages of Text_IO such as Text_IO.Integer_IO which can be instantiated with the INTEGER type as follows:
     

     
          package Int_IO is new Integer_IO(INTEGER); use Int_IO;
     

     Add the line of code above to the declaration section of the Table procedure and recompile the program. The remaining error messages (none will have the description, "invalid parameter list ...") are the result of small syntactic errors that you should be able to fix. Fix those now.
   • Run Table and note the output. Note the columns headers are not centered over the columns. Fix the program so that they are (Hint...change the constant declarations to the appropriate number of characters). Recompile and run to verify the change has worked.
   • The program prints one line of powers of 2. Modify the program so that it prints powers of the numbers 2,3,4, ...,20 (one line each). Compile and run it to make sure it works (fix as necessary).
   • Now, modify the program so that an appropriate title is printed over the entire table, centered over the column headings, e.g.,

                                    TABLE OF POWERS
                                    ===== == ======
     
                                         .....
     

   • Hand in your corrected program by submitting it to your ftp directory for this class.

   
   

2. Part 2: Writing a program
   To complete this assignment, you will need to use IF-THEN-ELSE statements and FLOATing point arithmetic.
   1. The program Description:
      Write an Ada program called "Triangle" which reads the lengths of 3 sides of a triangle and determines if the triangle is "obtuse."
      Definition: A triangle having sides A, B, and C, where C is a side of maximal length, is "obtuse" if A*A + B*B < C*C

   2. Input to the Program:
      The user of your program will enter three FLOAT values A, B and C, representing the lengths of the sides of a triangle, where the last length C will be no smaller than A and B. You may assume the input is typed correctly.
      The program will then determine whether the triangle is obtuse or not, and will print an appropriate message.

   3. Sample Output:
      Your program should issue a prompt to the user, asking for the three sides of the triangle. Below are some sample runs of the program (user responses appear in italix)

      (Run 1)
      Enter the sides of a triangle (put the longest length last):
        5.0  4.0   6.0 
      The triangle is not obtuse.
      
      (Run 2)
      Enter the sides of a triangle (put the longest length last):
        3.0  4.0   6.0 
      The triangle is obtuse.
      

   4. Ada Packages that you will need to use:
      You will need the package "Text_IO" in order for your program to use GET, PUT and NEWLINE for text data. You will also need to input and output floating point numbers which will require instantiating a generic child package of Text_IO with the FLOAT type as follows:
      

      
      
            with Text_IO; use Text_IO;
            procedure Triangle is
                package Flt_IO is new Float_IO(INTEGER); use Flt_IO;
                ...
      
            begin 
      

   5. Handing in your program:
      Hand in your program by submitting it to your ftp directory for this class.

      More Information on Ada

      Here is a little bit more information about the Text_IO package. There are also several good Ada web sites, I've listed a few of them here.