This becomes tedious or at times impossible, if all developers do not follow some standard programming style to code the program.Īn appropriate programming style includes using function and variable names relevant to the intended task, using well-placed indentation, commenting code for the convenience of reader and overall presentation of code.
When multiple programmers work on the same software project, they frequently need to work with the program code written by some other developer. Programming style is set of coding rules followed by all the programmers to write the code. λ-expressions are executed by evaluating them as they occur.Ĭommon Lisp, Scala, Haskell, Erlang and F# are some examples of functional programming languages. Λ-calculus - Most functional programming languages use λ-calculus as their type systems. Non-strict evaluation does not evaluate the expression unless it is needed.
Strict evaluation always evaluates the expression before invoking the function. Functional programming has two types of evaluation methods, strict (eager) or non-strict (lazy). Strict evaluation - It is a method of evaluating the expression passed to a function as an argument. Recursion is the way of creating loops in functional programming. Recursion - Recursion is a programming technique where a function calls itself and repeats the program code in it unless some pre-defined condition matches. Pure functions - These functions do not include destructive updates, that is, they do not affect any I/O or memory and if they are not in use, they can easily be removed without hampering the rest of the program. This makes it possible to predict the behavior of the program.įunctional programming uses the following concepts:įirst class and High-order functions - These functions have capability to accept another function as argument or they return other functions as results. This is a property as well as a drawback of procedural programming, in which the sequence or timing of the procedure execution becomes important.įunctional programming provides means of computation as mathematical functions, which produces results irrespective of program state. In procedural programming, it is possible for a procedure to produce different results when it is called with the same argument, as the program itself can be in different state while calling it. While control flow is transferring from one procedure to another, the program changes its state. the control of program is transferred to the called procedure. In procedural languages, the flow of the program runs through procedures, i.e. A function in mathematics should always produce the same result on receiving the same argument. Structured programming uses control structure, which controls the flow of the program, whereas structured coding uses control structure to organize its instructions in definable patterns.įunctional programming is style of programming language, which uses the concepts of mathematical functions. Structured Coding - In reference with top-down analysis, structured coding sub-divides the modules into further smaller units of code in the order of their execution.
Jumps are prohibited and modular format is encouraged in structured programming. It discourages jumps using ‘goto’ statements in the program, which often makes the program flow non-traceable. Modular programming based on the understanding of top-down analysis. These groups are known as modules, subprograms or subroutines. Modular Programming - While programming, the code is broken down into smaller group of instructions.
Each problem is individually solved and steps are clearly stated about how to solve the problem. Under top-down analysis, the problem is broken down into small pieces where each one has some significance. Thus it is very important that we understand how to solve the problem. This rational work is known as problem in the software parlance. Top-down analysis - A software is always made to perform some rational work. Structured programming uses three main concepts: Structured programming states how the program shall be coded. It encourages the developer to use subroutines and loops instead of using simple jumps in the code, thereby bringing clarity in the code and improving its efficiency Structured programming also helps programmer to reduce coding time and organize code properly. The solution to this is structured programming. If one forgets how software and its underlying programs, files, procedures are constructed it then becomes very difficult to share, debug and modify the program. Gradually, it becomes next to impossible to remember the flow of program. In the process of coding, the lines of code keep multiplying, thus, size of the software increases. In this chapter, we will study about programming methods, documentation and challenges in software implementation.