ISBN : 978-81-963532-2-3 (E-Book) developaprogramusingthatlanguage.Thisresultagreeswiththeintuitivenotionthatittakesmoreeffort to develop a program in assembly language than to develop a program in a high-levellanguageto solve aproblem. EffortandTime The effort required to develop a program can be obtained by dividing the program volume withtheleveloftheprogramminglanguageusedtodevelopthecode.Thus,effortE=V/L,whereEis the number of mental discriminations required to implement the program and also the effortrequired to read and understand the program. Thus, the programming effort E = V²/V* (since L =V*/V) varies as the square of the volume. Experience shows that E is well correlated to the effortneededfor maintenanceofan existingprogram. The programmer’s time T = E/S, where Sthe speed of mentaldiscriminations.The value of Shas been empirically developed from psychological reasoning, and its recommended value forprogrammingapplications is 18. LengthEstimation Even though the length of a program can be found by calculating the total number of operatorsand operands in a program, Halstead suggests a way to determine the length of a program usingthe number of unique operators and operands used in the program. Using this method, theprogram parameters such as length, volume, cost, effort, etc. can be determined even before thestartofanyprogramming activity. His method issummarized below. Halstead assumed that it is quite unlikely that a program has several identical parts – in formallanguageterminology any program of length N consists identicalsubstrings– oflengthgreaterthanη(ηbeingtheprogramvocabulary). In fact, once a piece of code occurs identically at several places, it is made into aprocedure or a function. Thus, it can be assumed that ηuniquestringsoflengthη.Now,itisstandardcombinatorialresultthatforany givenalphabetof r 158 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal of N/
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