Basics of Programming

Mrs Sangeeta Bhandari

PG Department of Computer Science & IT

HMV, Jalandhar

Contents

Computer Programming Languages

• And Flowcharts
• We will learn
• Computer Programming Languages.
• Non-computational languages
• Machine language
• Example
• Assembly language
• Example
• High level language
• Examples.

Programming

• Computer programming is the process of performing a particular computation, usually by designing and building an executable computer program. Programming involves tasks such as analysis, generating algorithms, profiling algorithms' accuracy and resource consumption, and the implementation of algorithms.

Flowchart

• A flowchart is a diagram that depicts a process, system or computer algorithm. They are widely used in multiple fields to document, study, plan, improve and communicate often complex processes in clear, easy-to-understand diagrams.

Flowchart Symbols

• Flowcharts use special shapes to represent different types of actions or steps in a process. Lines and arrows show the sequence of the steps, and the relationships among them. These are known as flowchart symbols.

Flowchart Symbols

Flow chart of the while loop :

Flow chart of the for loop:

The flow chart of the if statement:

The flow chart of the if…else statement:

The flow chart of the switch statement:

Flowchart for finding the sum of first five natural numbers ( i.e. 1,2,3,4,5):

Flowchart (Example):

Flowchart to find the sum of first 50 natural numbers.

Start

Read A, B

Is A > B

Print A

Print B

End

Yes

No

Flow Chart to find largest of two numbers:

Flowchart to find the largest of three numbers A,B, and C:

NO

LIMITATIONS OF USING FLOWCHARTS:

• Complex logic: Sometimes, the program logic is quite complicated. In that case, flowchart becomes complex and clumsy.

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• Alterations and Modifications: If alterations are required the flowchart may require re-drawing completely.

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• Reproduction: As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem.

Flowchart (Exercise):

1. Draw a flowchart to depict all steps that you do reach your college.

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• Draw Flowchart for Linear search.

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Computer Programming Languages:

• A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer

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• Programming languages, like human languages, are defined through the use of syntactic and semantic rules, to determine structure and meaning respectively.

Computer Programming Languages (Contd…):

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• Programming languages are used to facilitate communication about the task of organizing and manipulating information, and to express algorithms precisely.

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• For 50 years, computer programmers have been writing code. New technologies continue to emerge, develop, and mature at a rapid pace. Now there are more than 2,500 documented programming languages!

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Non-computational languages:

• Non-computational languages, such as markup languages like HTML or formal grammars like BNF, are usually not considered programming languages.

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• Often a programming language is embedded in the non-computational language.

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Machine language:

• It is the lowest-level programming language.

• Machine languages are the only languages understood by computers.

Machine language:

• While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers.

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For example, an x86/IA-32 processor can execute the following binary instruction as expressed in machine language:

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Binary: 10110000 01100001 (Hexadecimal: 0xb061)

Assembly Level Language:

• An assembly language is a low-level language for programming computers.

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• The word "low" does not imply that the language is inferior to high-level programming languages but rather refers to the small or nonexistent amount of abstraction between the language and machine language, because of this, low-level languages are sometimes described as being "close to the hardware."

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• It implements a symbolic representation of the numeric machine codes and other constants needed to program a particular CPU architecture.

Assembly Level Language

• A utility program called an assembler, is used to translate assembly language statements into the target computer's machine code.
• The assembler performs a more or less isomorphic translation (a one-to-one mapping) from mnemonic statements into machine instructions and data.

Example: Assembly language representation is easier to remember (more mnemonic)

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mov al, 061h

This instruction means:

Move the hexadecimal value 61 (97 decimal) into the processor register named "al".

The mnemonic "mov" is an operation code or opcode, A comma-separated list of arguments or parameters follows the opcode;

Example (Adds 2 numbers):

name "add"

mov al, 5 ; bin=00000101b

mov bl, 10 ; hex=0ah or bin=00001010b

add bl, al ; 5 + 10 = 15 (decimal) or hex=0fh or

bin=00001111b

High-level language:

• High-level languages are relatively easy to learn because the instructions bear a close resemblance to everyday language, and because the programmer does not require a detailed knowledge of the internal workings of the computer.

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• Each instruction in a high-level language is equivalent to several machine-code instructions, therefore it is more compact than equivalent low-level programs.

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• High-level languages are used to solve problems and are often described as problem-oriented languages

High-level language

Examples of HLL:

• BASIC was designed to be easily learnt by first-time programmers;
• COBOL is used to write programs solving business problems;
• FORTRAN is used for programs solving scientific and mathematical problems.
• With the increasing popularity of windows-based systems, the next generation of programming languages was designed to facilitate the development of GUI interfaces;

for example, Visual Basic wraps the BASIC language in a graphical programming environment.

• Support for object-oriented programming has also become more common, for example in C++ and Java.

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Example (C program to add 2 numbers):

#include<stdio.h> //header files

Void main()

{

int a, b, c; // declaration of 3 variables

printf(“Enter two numbers:\n”);

Scanf(“%d”, &a); // read 1^st number

Scanf(“%d”, &b); // read 2^nd number

c=a+b; // compute the sum

printf(“Sum of 2 numbers is %d”, c); //print sum

}

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• ThankYou !!!