ALGORITHMS, FLOWCHARTS, DATA TYPES. AND PSEUDOCODE. ALGORITHMS. The term algorithm originally referred to any computation performed via. What is Pseudocode? An algorithm is a sequence of instructions to solve a well- formulated computational problem specified in terms of its input and output. Pseudocode What is pseudocode? Pseudocode is a simplified, half-English, half-code outline of a com- puter program. Why use it? • Because it can help.
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PDF | On Aug 1, , Nicholas Bennett and others published Introduction to Algorithms and Pseudocode. Pseudo-code is an informal way to express the design of a computer program or an algorithm in. The aim is to get the idea quickly and also easy to read. Pseudo Code Practice Problems: Listed below is a brief explanation of Pseudo code as well as a list of examples and solutions. Pseudo code. Pseudo code can .
This standard often varies between institutions and teachers. Not lines 2. However, the similarity to natural language is usually more cosmetic than genuine. Beyond this, flowcharts serve the programmer in two distinct ways: Write a program to calculate the sum and average of a series of numbers. In other word, an algorithm is a step-by-step procedure to solve a given problem Alternatively, we can define an algorithm as a set or list of instructions for carrying out some process step by step. You might even want to get rid of any coding commands altogether and just define each line's process in plain language.
As you develop your pseudocode into actual code, you will need to transcribe it into a programming language — so it can help to structure your outline with this in mind. You might even want to get rid of any coding commands altogether and just define each line's process in plain language. For example, "if input is odd, output 'Y'" might become "if user enters an odd number, display 'Y'" instead. Write the purpose of the process. Write the initial steps that set the stage for functions.
Write only one statement per line. Capitalize the initial keyword of each main direction. Write what you mean, not how to program it. Use standard programming structures. Use blocks to structure steps. Add comments if necessary. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Together, they cited information from 8 references.
Learn more. Learn more Know what pseudocode is. Pseudocode is a step-by-step written outline of your code that you can gradually transcribe into the programming language. Many programmers use it to plan out the function of an algorithm before setting themselves to the more technical task of coding. Understand why pseudocode is useful. Pseudocode is used to show how a computing algorithm should work. Coders often use pseudocode as an intermediate step in programming in between the initial planning stage and the stage of writing actual executable code.
Some other uses of pseudocode include the following: Describing how an algorithm should work. Pseudocode can illustrate where a particular construct, mechanism, or technique could or must appear in a program. Explaining a computing process to less-technical users. Computers need a very strict input syntax to run a program, but humans especially non-programmers may find it easier to understand a more fluid, subjective language that clearly states the purpose of each line of code.
Designing code in a group setting. High-level software architects will often include pseudocode into their designs to help solve a complex problem they see their programmers running into. If you are developing a program along with other coders, you may find that pseudocode helps make your intentions clear. Remember that pseudocode is subjective and nonstandard.
There is no set syntax that you absolutely must use for pseudocode, but it is a common professional courtesy to use standard pseudocode structures that other programmers can easily understand. If you are working with others on a project—whether they are your peers, junior programmers, or non-technical collaborators—it is important to use at least some standard structures so that everyone else can easily understand your intent. If you are enrolled in a programming course at a university, a coding camp, or a company, you will likely be tested against a taught pseudocode "standard".
This standard often varies between institutions and teachers. Focus on the main purpose of pseudocode. It can be easy to revert to writing in code once you hit your stride. Remembering the purpose of your pseudocode—explaining what each line of the program should do—will keep you grounded while creating the pseudocode document. Use a plain-text editor. It can be tempting to use a word processor e. Start by writing down the purpose of the process.
Dedicating a line or two to explaining the purpose of your code will help set up the rest of the document, and it will also save you the task of explaining the program's function to each person to whom you show the pseudocode. Each statement in your pseudocode should express just one action for the computer.
In most cases, if the task list is properly drawn, then each task will correspond to one line of pseudocode. Consider writing out your task list, then translating that list into pseudocode, then gradually developing that pseudocode into actual, computer-readable code. Use white space and indentation effectively. Using white spaces between "blocks" of text will help keep different components of your pseudocode isolated, and indenting different pieces of each block will indicate that those pieces of pseudocode go under a less-indented section.
For example, a section of pseudocode that discusses entering a number should all be in the same "block", while the next section e. Capitalize key commands if necessary. Depending on your pseudocode requirements or the environment in which you're publishing the pseudocode, you may need to capitalize commands that will remain in the actual code. For example, if you use "if" and "then" commands in your pseudocode, you might want to change them to read "IF" and "THEN" e.
For a computer to perform a desired task, a method for carrying out some sequence of events, resulting in accomplishing the task, must somehow be described to the computer.
The algorithm can be described on many levels because the algorithm is just the procedure of steps to take and get the result. The language used to describe an algorithm to other people will be quite different from that which is used by the computer, however the actual algorithm will in essence be the same.
An example of an algorithm people use would be a recipe to make a cake. Mix all the ingredients, except the oil, in a deep bowl. MT Programming Design Page no: Put 1" water in wide pot, then place deep bowl of batter inside.
Cover pot tightly and steam 15 min. Heat oil very hot and pour over custard. Steam 5 more min. Serves 4 people" This breaks down 'Making Chinese egg custard' into smaller steps.
To make the product one still needs to know how to execute each of the steps in the procedure and understand all of the terms. A procedure is a finite sequence of well-defined instructions, each of which can be mechanically carried out in a finite amount of time.
The procedure must break up the problem solution into parts that the recipient party can understand and execute. In the case of a computer, the problem solution is usually in the form of a program that encompasses the algorithm and explains to the computer a clearly defined procedure for achieving the solution. The procedure must consist of smaller steps each of which the computers understand.
There may be no ambiguities in the translation of the procedure into the necessary action to be taken.
A program is then just a specific realisation of an algorithm, which may be executed on a physical device. A computer is essentially a physical device designed to carry out a collection of primitive actions. A procedure is a sequence of instructions written in terms of which evoke a proper operation.
To make effective use of an algorithm on a computer one must not only find and understand a solution to the problem but also convey the algorithm to the computer, giving the correct sequence of understood commands that represent the same algorithm. An algorithm is procedure consisting of a finite set of unambiguous rules instructions which specify a finite sequence of operations that provides the solution to a problem, or to a specific class of problems for any allowable set of input quantities if there are inputs.
In other word, an algorithm is a step-by-step procedure to solve a given problem Alternatively, we can define an algorithm as a set or list of instructions for carrying out some process step by step. A recipe in a cookbook is an excellent example of an algorithm. The recipe includes the requirements for the cooking or ingredients and the method of cooking them until you end up with a nice cooked dish.
In the same way, algorithms executed by a computer can combine millions of elementary steps, such as additions and subtractions, into a complicated mathematical calculation. Also by means of algorithms, a computer can control a manufacturing process or co- MT Algorithms for such large-scale processes are, of course, very complex, but they are built up from pieces. One of the obstacles to overcome in using a computer to solve your problems is that of translating the idea of the algorithm to computer code program.
People cannot normally understand the actual machine code that the computer needs to run a program, so programs are written in a programming language such as C or Pascal, which is then converted into machine code for the computer to run. In the problem-solving phase of computer programming, you will be designing algorithms.
This means that you will have to be conscious of the strategies you use to solve problems in order to apply them to programming problems. These algorithms can be designed though the use of flowcharts or pseudocode. A flowchart is a diagram made up of boxes, diamonds and other shapes, connected by arrows - each shape represents a step in the process, and the arrows show the order in which they occur. Flowcharting combines symbols and flowlines, to show figuratively the operation of an algorithm.
In computing, there are dozens of different symbols used in flowcharting there are even national and international flowcharting symbol standards. In business process analysis, a couple of symbols are sufficient. A box with text inside indicates a step in the process, while a diamond with text represents a decision point.
See the figure for an example. If the flowchart is too messy to draw, try starting again, but leaving out all of the decision points and concentrating on the simplest possible course. Then the session can go back and add the decision points later. It may also be useful to start by drawing a high-level flowchart for the whole organisation, with each box being a complete process that has to be filled out later. From this common understanding can come a number of things - process improvement ideas will often arise spontaneously during a flowcharting session.
And after the session, the facilitator can also draw up a written procedure - a flowcharting session is a good way of documenting a process. Process improvement starts with an understanding of the process, and flowcharting is the first step towards process understanding.
This is not a complete list of all the possible flowcharting symbols, it is the ones used most often in the structure of Assembly language programming. Predefined Process Used to invoke a subroutine or an interrupt program.
Terminal Indicates the starting or ending of the program, process, or interrupt program. Flow Lines Shows direction of flow. Generally, there are many standard flowcharting symbols. General Rules for flowcharting 1. All boxes of the flowchart are connected with Arrows. Not lines 2. Flowchart symbols have an entry point on the top of the symbol with no other entry points. The exit point for all flowchart symbols is on the bottom except for the Decision symbol. The Decision symbol has two exit points; these can be on the sides or the bottom and one side.
Generally a flowchart will flow from top to bottom. However, an upward flow can be shown as long as it does not exceed 3 symbols. Connectors are used to connect breaks in the flowchart.
Examples are: Subroutines and Interrupt programs have their own and independent flowcharts. All flow charts start with a Terminal or Predefined Process for interrupt programs or subroutines symbol.
All flowcharts end with a terminal or a contentious loop. The standardised format provides a common method for people to visualise problems together in the same manner. The use of standardised symbols makes the flow charts easier to interpret, however, standardising symbols is not as important as the sequence of activities that make up the process.
Do not document the way a written process or a manager thinks the process happens. If the desired or theoretical process is charted, problems with the existing process will not be recognised and no improvements can be made. If Note all circumstances actually dealt with. A better approach would be to have someone unfamiliar with the process try to follow the flow chart and note questions or problems found.
These steps are sometimes left out because of familiarity with the process, however, represent sources of problems due to a possible lack of information used to make the decision can be inadequate or incorrect if performed by a different person. Examples of Algorithms and Flowcharts Example 1. Design an algorithm and the corresponding flowchart for adding the test scores as given below: Start 2.
Get the first testscore 4. Add first testscore to sum 5. No standard for pseudocode syntax exists, as a program in pseudocode is not an executable program. Pseudocode resembles, but should not be confused with, skeleton programs which can be compiled without errors.
Flowcharts , drakon-charts and Unified Modeling Language UML charts can be thought of as a graphical alternative to pseudocode, but are more spacious on paper. Its main use is to introduce students to high level languages through use of this hybrid language.
Textbooks and scientific publications related to computer science and numerical computation often use pseudocode in description of algorithms, so that all programmers can understand them, even if they do not all know the same programming languages. In textbooks, there is usually an accompanying introduction explaining the particular conventions in use.
The level of detail of the pseudocode may in some cases approach that of formalized general-purpose languages.
A programmer who needs to implement a specific algorithm, especially an unfamiliar one, will often start with a pseudocode description, and then "translate" that description into the target programming language and modify it to interact correctly with the rest of the program.
Programmers may also start a project by sketching out the code in pseudocode on paper before writing it in its actual language, as a top-down structuring approach, with a process of steps to be followed as a refinement.
As the name suggests, pseudocode generally does not actually obey the syntax rules of any particular language; there is no systematic standard form, although any particular writer will generally borrow style and syntax; for example, control structures from some conventional programming language.
Variable declarations are typically omitted. Function calls and blocks of code, such as code contained within a loop, are often replaced by a one-line natural language sentence. Depending on the writer, pseudocode may therefore vary widely in style, from a near-exact imitation of a real programming language at one extreme, to a description approaching formatted prose at the other.
This is an example of pseudocode for the mathematical game fizz buzz:. In numerical computation , pseudocode often consists of mathematical notation , typically from set and matrix theory, mixed with the control structures of a conventional programming language, and perhaps also natural language descriptions.
This is a compact and often informal notation that can be understood by a wide range of mathematically trained people, and is frequently used as a way to describe mathematical algorithms. For example, the sum operator capital-sigma notation or the product operator capital-pi notation may represent a for-loop and a selection structure in one expression:.
Here follows a longer example of mathematical-style pseudocode, for the Ford—Fulkerson algorithm:.