Computer Programming Lecture - University of Mines PDF

Department of Computer Science & Engineering UNIVERSITY OF MINES AND TECHNOLOGY COMPUTER PROGRAMMING BY: DR MILLICENT AGANGIBA Presentation Outline Introduction to programming Data types Variables Declaration of variables Assignment...

Department of Computer Science & Engineering UNIVERSITY OF MINES AND TECHNOLOGY COMPUTER PROGRAMMING BY: DR MILLICENT AGANGIBA Presentation Outline Introduction to programming Data types Variables Declaration of variables Assignment Operators COURSE DESIGN ۞ Course Code: GL/MN-351 ۞Credits: (2,1,2) ۞Prerequisites: Computer Programming ۞References ◦Title: C# Programming From Problem Analysis to Program Design, 5th Edition or 3rd Edition. ◦Author: Barbara Doyle ◦Publisher: Cengage, 1088 pp, 2016 or 832pp, 2010 COURSE OUTLINE ۞Elements of programming. ۞Data description statements. ۞Control structures. ۞Data types. ۞Data-processing statements. ۞Input and output (I/O) statements. COURSE OUTLINE ۞Procedure for writing algorithms ۞Building application. ۞Steps in developing application. ۞Decisions. ۞Conditions and loops. ۞Arithmetic operators. ۞Programming applications in Engineering. EVALUATION METHODS ۞Assignments ۞Labs ۞Quizzes ۞Final Exam INTRODUCTION ۞A "programming language" is a medium designed to allow humans to give instructions or describe consecutive actions to be executed by a computer. ۞The language used by the processor is called machine code. ۞The code that reaches the processor consists of a series of 0s and 1s known as binary data. INTRODUCTION ۞Machine code is therefore difficult for humans to understand ۞Hence, the need for intermediary languages, which can be understood by humans. ۞The code written in this type of language is translated into machine code using compilers and interpreter for the computer to process. INTRODUCTION There are several basis for classifying programming languages: ۞Based on Levels of Abstraction ۞Based on How codes are Translated to Machine Code ۞Based on Programming Paradigm. INTRODUCTION Classification Based on: Based on Levels of Abstractions ۞Low Level Languages ۞High Level Languages CATEGORIES TWO CLASSES OF PROGRAMMING LANGUAGES: Low Level Languages High Level Languages Designed to program the computer at High level of abstraction i.e Closer to very low-level of abstraction; i.e. Machine human understanding; Level Needs translation by compiler or Little or no abstraction i.e Closer to interpreter Machine understanding; Machine Independent languages Difficult for humans. Eg. C++, VB, C#. Machine dependent languages Eg. Machine Language, Assembly Language. INTRODUCTION Classification Based on: How codes are Translated to Machine Code: ۞Compiled languages ۞Interpreted languages ۞Intermediary language TRANSLATION COMPILED, INTERPRETED, OR INTERMEDIARY LANGUAGE? Main application Compiled/interpret Language area ed ADA Real-time Compiled BASIC Educational purposes Interpreted C System programming Compiled System object C++ Compiled programming TRANSLATION COMPILED, INTERPRETED, OR INTERMEDIARY LANGUAGE? Language Main application area Compiled/interpreted Cobol Management Compiled Fortran Calculation Compiled Internet oriented Java Intermediary programming MATLAB Mathematical calculations Interpreted language Classification Classification Based on: Based on Programming Paradigm: ۞Object- oriented ۞Imperative or procedural ۞Concurrent ۞Functional ۞Scripting In this course, we would practice Computer Programming using C#. FEATURES OF C# I. Simple. II. Modern programming language. III. Object oriented. IV. Type safe. V. Interoperability. VI. Scalable and Updateable. VII. Component oriented. VIII.Structured programming language. STRUCTURE OF C# Basic C# program consists of the following things. ✓Namespace declaration ✓A Class ✓The Main method ✓Statements and Expressions ✓Comment EXAMPLE OF C# PROGRAM using System; namespace HelloWorldApplication Namespace { class HelloWorld Class { static void Main(string[] args) Main method { Comment Console.WriteLine("Hello World"); Statement } } } IMPORTANT THINGS TO NOTE (C#) ۞C# is case sensitive. ۞C# program execution starts at the Main method. ۞All C# expression and statements must end with a semicolon (;). ۞ File name is different from the class name. Data Types Data Types ۞The type of data that a variable declaration specifies and defines what type of information will be stored in the allocated memory space. ۞Each time a variable is declared, C# requires that the variable data type is specified. This is because C# is a strongly typed language. Therefore prior to using a variable, the compiler must be aware of it….aware of what type of data is expected. Data Types  Data types In the C# programming language, data types are divided in three categories: ❑value types ❑reference types ❑pointer types Data types Data Variables ۞are memory/storage locations that hold data that can be changed during project execution. ۞Every variable has a type that determines what values can be stored in the variable ۞Used in programming for storing values, calculating and for reusability. Constants ۞Memory locations that hold data that cannot be changed during project execution ۞declared using the keyword CONST and are given a name, a data type, and a value ۞Syntax const type identifier = expression; Declaring a Variable ۞When you declare a variable or a named constant, the compiler reserves an area of memory and assigns it a name, called an identifier. ۞Identifier names are specified according to the rules of recommended naming conventions. ۞The syntax of declaring a variable is as follows: DataType VariableName; Declaring a Variable ۞Identifier ۞Name Rules for creating an identifier ✓Combination of alphabetic characters (a-z and A-Z), numeric digits (0- 9), and the underscore ✓First character in the name may not be numeric ✓No embedded spaces – concatenate (append) words together ✓Keywords cannot be used ✓Use the case of the character to your advantage ✓Be descriptive with meaningful names ✓Follow naming conventions / general naming conventions  Declaring a Variable int studentCount; // number of students in the class int numberOfExams; // number of exams int coursesEnrolled; // number of courses enrolled Assignment To store a value in a variable you must use an =. Here is an example of how to store the value 5 inside an integer variable. MyInt = 5; You can store a value inside a variable when you declare it. This is called initializing the variable. int MyInt = 5; C# - Operators An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. C# has rich set of built-in operators and provides the following type of operators: Arithmetic Operators Relational Operators Logical Operators Assignment Operators Arithmetic Operations Arithmetic Operations ۞Following table shows all the arithmetic operators supported by C#. Assume variable A holds 10 and variable B holds 20 then An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. Arithmetic Operations Mathematical Functions: The common mathematical functions in C# include: Basic Arithmetic Operations int num = 100; messagebox.show (num++); // Displays 100 messagebox.show(num); // Display 101 messagebox.show(++num); // Displays 102 Relational Operators Following table shows all the relational operators supported by C#. Assume variable A holds 10 and variable B holds 20, then − Logical Operators Following table shows all the logical operators supported by C#. Assume variable A holds Boolean value true and variable B holds Boolean value false, then − Assignment Operators There are following assignment operators supported by C# −