| Project
July 2002
Question 1:
Specify, design and implement
a software tool that will compute
the Cyclomatic complexity for
the programming language of your
choice. Use the graph matrix as
the operative data structure in
your design.
Answer: Part - 3
Flow graph notation
Flow graph is the notation for
the representation of control
flow. The flow graph depicts logical
control flow using the notation
illustrated below.
Sequence
if
While
Until
Case
Each structured
construct has a corresponding
flow graph symbol. Each circle
called a flow graph node represents
one or more procedural statements.
A sequence of process boxes and
a decision diamond can map into
a single node. The arrows in the
flow graph called edges or links
represent flow of control and
are analogous to flowchart arrows.
An edge must terminate at a node
even if the node does not represent
any procedural statements. Areas
bound by edges and nodes are called
regions. When counting regions
we include the area outside the
graph as a region. In the C language
the conditional constructs are
if, while, case etc. When compound
conditions are encountered in
a procedural design, the generation
of a flow graph becomes slightly
more complicated. A compound condition
occurs when one or more Boolean
operators is present in a conditional
statement. A separate node is
created for each of the conditions
a and b in the statement if a
OR b. Each node that contains
a condition is called a predicate
node and is characterized by two
or more edges emanating from it.
3. From the control flow graph,
create the connection matrix.
The connection matrix is a kind
of graph matrix.
Graph matrices
The procedure for deriving the
flow graph and even determining
a set of basis paths is amenable
to mechanization. To develop a
soft ware tool that assists in
basis path testing, a data structure
called a graph matrix can be quite
useful. A graph matrix is a square
matrix whose size (ie number of
rows and columns) is equal to
the number of nodes on the flow
graph. Each row and column corresponds
to an identified node, and matrix
entries correspond to connections
(an edge) between nodes. An example
of a flow graph and its corresponding
graph matrix is shown here.
Cont...
|
