Software Measurements and Metrices

The size of a project is not the no. of bytes that the source code occupies

The Project size is a measure of the problem complexity in terms of the effort

and time required to develop the product.

Two metrices are widely used to estimate size among many metrices:

1. Line of Code (LOC)

2.Function point (FP)

1. Line of Code (LOC) :
   1.The Project size is estimated by counting the number of source
       instructions in the developed program (lines used for commenting the
       code & the header lines are ignored).

   2.To estimate the LOC count at the end of a project is a very simple
       job, to estimate the LOC at the begining , the project is divided into  
       modules and sub modules.

   Short Comings of LOC: 
   1.LOC gives a numerical value of problem size that can vary widely with  
      individual coding style.
   2.LOC only focuses on the coding activity alone, it only computes the
     no. of the sources lines in the final program.
   3.LOC measures corelates poorly with the quality and efficiency of the
      code .
   4.The LOC count can be accurately compute only after the code has  
      been fully developed. It is of little use to project manager during    
      planning.

2. Function Point Metric (FP):
    Function point metrics is used to :
   1  Estimate the cost or effort required to design ,code and test the s/w.
   2. To predict the no.of errors that will be encountered during testing.
   3. Forecast the no. of components or the no. of projected sources
       lines in the implemented system.
   4. This metric overcomes many of the shortcomings of the LOC metric.
   5. One  of the imp advantages of using the function point metric is that it
       can be used to easily estimate the size of a s/w product directly from
       the problem specification.
   6. A s/w product supporting many features would certainly be of larger
       size than a product with a less no.of features.

 Functon point is computed in two steps.
 - First step is to compute unadjusted function pt.(UFP).
 - In the second step technical complexity factor (TCF) is computed.

Difference :

S.No.	Function Point	Line of code
1.	Specification based	Analogy based
2.	Language Independent	Language Dependent
3.	User Oriented	Design Oriented
4.	Variations a function of Counting Conventions	Variations a function of languages
5.	Expandable to source lines of code	Convertible to function points