Flowchart and Computer Languages

Category : 7th Class

Flowchart and Computer Languages

 

Introduction

Computer programming language is defined as the type of language used for writing the source code of computer program, whereas, computer programs are set of instructions that enable a computer to interact with the user, peripherals and information. These instructions are written in a language called computer programming language. The process of writing computer programs is called computer programming. Before writing a computer program, first you have to develop an algorithm. An algorithm is a group of logical instruction that generates the output according to given input. These algorithms are written in Pseudocode. Pseudocode is an informal description of a computer program that is written in simple English.

 

While writing a program using a computer programming language, such as C, you need to follow the syntax of that language. A programming language also provide operators that enable you to perform various tasks, such as computing and manipulating values of variables, comparing values of different variables of same data types and testing multiple conditions. After developing algorithm, you need to develop flowchart.

 

How to Develop Flowchart

Flowchart is a technique that allows you to represent computer program graphically. Each step in the flowchart is represented by a different symbol and contains a short description of the step. Using flowchart, you can easily understand the logic of a program. A flowchart represents the logical and operational steps to be performed within the system for transforming the input process into output. Flowchart serves as a basis for discussion and communication between the system analysts and the programmers.

 

To create a flowchart, you need to use the following symbols:

 

Symbol

Description

This symbol is used to represent the start and end of an algorithm or process. It is also called terminator box.

This symbol is used to represent the logic used in a process or algorithm. It is also called processing box.

This symbol is used to represent the input/output steps of a process. It is also called data box.

This symbol is used to represent the conditional situation of a process. It is also called decision making box.

These symbols are used to represent the flow of control in a process.

 

Rules for Creating a Flow Chart

 

v  While creating a flow chart, only a single flow line comes out from a process symbol.

v  Flow direction of a process will always indicate either from left to right or from top to bottom, as shown in the following figure:

 

 

v  In decision box, only one flow line enters and multiple flow lines can come out, as shown in the following figure:

 

 

v  Only a single flow line comes out from starting process and enters single flow line in stop process, as shown in the following figure.

 

 

v  Every flowchart must have only one logical start and one logical end.

 

Look at the following flow chart to find the greatest of three numbers, X, Y and Z:

 

Types of Programming Language

Basically, there are two types of programming language.

1. Low Level Programming Language

2. High Level Programming Language

 

Low Level Programming Language

A type of programming language that provides machine understandable and dependable codes is known as Low Level Language. The low Level Languages are very close to machine code (Os and Is). The numbers 0 and 1 are known as binary numbers. All programming instructions of this language are written in binary form and assembly language codes. Hence, Assembly language and Machine language are the common examples of low level programming language.

 

Advantages of Low Level Programming Language

 

v  Low level language allows user to develop program faster and memory efficient.

v  The translation of source code to machine code is not needed. Hence, it reduces the compilation and interpretation time.

v  Using a low level language, programmers can use processor and memory in better way.

v  Low level languages can directly communicate with hardware devices.

v  It provides direct control of computer storage and registers.

 

Low Level Programming Languages are sometimes divided into two categories:

 

1. First Generation (1GL): It is the machine language. This language is directly processed by microprocessor. There is no need of any translator. Instructions written in machine language are dependent on machine and changes from one computer to other.

 

2. Second Generation (2GL): It is also known as assembly language. It is also a low level language but is different from machine language. Instead of using binary sequence to represent a program, it uses mnemonic codes.

 

Mnemonic codes are short abbreviations that are used to provide instructions to a computer. To translate these mnemonic codes into machine codes, assembly language uses a special program called assembler.

The translated machine code is directly understood by microprocessor. Assembly language also includes macros. Basically macros are used as program instructions. They work like built in functions.

 

High Level Programming Language

High level programming language is closer to human languages. They do not directly interact with the hardware. Simple English statements are used to write program n high level language. These statements are needed to convert into machine language. For this, compilers/interpreters are used.

 

  • Compiler: A compiler is a special program used to translate statements written in a particular programming language into machine language. It scans the complete program and translates it as a whole into machine code programming languages such as C, C++, Java, etc. use compilers.
  • Interpreter: It is also used to translate statements written in a particular programming language into machine language. But unlike assembler it translates one statement at a time. Programming languages such as Ruby, Python, etc. use interpreter.

 

FORTRAN, C, COBOL (Common Business-Oriented Language), Prolog and PASCAL are some of the common examples of High Level Language. FORTRAN is mostly used for scientific calculations and COBOL is used for business purposes.

 

Advantages of High Level Programming Language

 

v  High level languages are user friendly, easy to write, debug and maintain.

v  They are machine independent language.

v  They provide higher level of abstraction as compared to machine language.

v  The chance of error is very less and errors can be find and debug easily.

v  They are easy to learn.

 

Types of High Level Programming Language

High level programming language can be further divided into three types.

 

1. OOP (Object-Oriented Programming) Language: is based on Object-Oriented Programming Model. It include classes, objects, methods, relationships and other processes for software designing. C++ and Java are the examples of OOP language.

 

2. Procedural Language: It provide a series of well-structured steps and procedures within its programming context to develop a program. FORTRAN, COBOL, PASCAL and ADA are the examples of procedural language.

 

3. Non-Procedural Language: It is a type of high level language in which we have to specify only 'what to do' and not 'how to do'. SQL (Structured Query Language) and RPG (Report Program Generator) are the examples of non- procedural language.



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