ISBN : 978-81-963532-2-3 (E-Book) Fig.31.1: Systemfunction asa mapof inputdatatooutput data Besides using the number ofinput and output data values,function point metric computesthesize of a software product (in units of functions points or FPs) using three other characteristics ofthe product as shown in the following expression. The size of a product in function points (FP)canbeexpressedastheweightedsumofthesefiveproblemcharacteristics.Theweightsassociatedwi ththefivecharacteristicswereproposedempiricallyandvalidatedbytheobservations over many projects. Function point is computed in two steps. The first step is tocomputethe unadjusted function point (UFP). UFP=(Numberofinputs)*4+(Numberofoutputs)*5+(Numberofinquiries)*4+(Numberoffi les)*10+ (Numberofinterfaces)*10 Numberofinputs:Eachdataiteminputbytheuseriscounted.Datainputsshouldbedistinguishedfromus erinquiries.Inquiriesareusercommandssuchasprint-account-balance. Inquiries are counted separately. It must be noted that individual data items input by the user arenot considered in the calculation of the number of inputs, but a group of related inputs 149 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal
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