Class II - Some FORTRAN Basics - Assignment

This ftp site has a bunch of demo Fortran programs. For each Fortran file I specify, read each program to get a feel for what it does, and then copy the text of the file, compile it, and execute it.

In each case, not every line is indented 6 spaces, so either make sure that each line is indented at least 6 spaces, or else save as *.f90. Otherwise, you will get a syntax error.

1) A Kind is an integer specification of data type for primitives, in general matching the sizeof the data type in bytes. Read this webpage for more details.

Compile and run this program.

2) Data types can be defined with the keyword TYPE. Members can be accessed with %.
Compile and run this program, which creates and uses a derived type for intervals. As requested in the comment, change the program so that it prints the interval length instead.

Compile and run this program which demonstrates nested types.

3) Pointers:
Read this document about FORTRAN pointers and array pointers. Then, compile and run this program. Modify the program as suggested in the comments and see what happens.

4) Do Loop and Cycle
This example demonstrates a do loop, equivalent to a for loop. Cycle is the equivalent of continue in C++.

5) Nested do loops with names, in this example.
Exit is equivalent to break. Note that we can break out of multiple levels of loop because of the named loops. This is similar to the labelled breaks in Java.

6) Select Case statement, as we have in VB6. Note this case statement works for ranges. Example here and here.

7) Functions.
Example here. Note that just as in C, the types of parameters are not specified in the declaration, but just the names. The types are specified subsequently. LOGICAL means boolean. Note the INTENT keyword, which is used to specify that these parameters are being passed in but not out of the program. Note that the function name is also assigned a type, = to the return type, and that assigning to the function name has the effect of specifying the return value. This is also found in VB6.

8) Arrays.
Note that the : character is used to specify a range. 2:5 means 2 through 5. Either side can be optional. The , character separates indexes when dealing with a matrix. Thus, in C++:
a[7][3]
would be written a[7,3] in FORTRAN
Try out this example and compare the source with the output carefully.

9) Intended Assignments:
A) Write a program that takes N as input, reads in N numbers into an array, and prints any number A[i] which is larger than the average.
B) Take advantage of the built in matrix manipulation functions in FORTRAN to write a program that takes in N, the size of a directed graph, followed by a series of edges, terminated by -1. Compute whether the graph is strongly connected.
C) Take advantage of the full capabilities of FORTRAN 90. Write a program that will take in a series of numbers, terminates by -1, and stores them in a binary search tree. Then take another series of numbers as input and output whether the numbers are in the binary tree. (All you need implement is insert and search).