Introduction to Programming Concepts

Course Design

• Course code is GL/MN-351
• Course credits are (2,1,2)
• The course prerequisite is Computer Programming
• A reference is "C# Programming From Problem Analysis to Program Design, 5th Edition or 3rd Edition" by Barbara Doyle, published by Cengage in 2016 (1088 pp) or 2010 (832pp)

Course Outline

• Elements of programming
• Data description statements
• Control structures
• Data types
• Data-processing statements
• Input and output (I/O) statements
• Procedure for writing algorithms
• Building applications
• Steps in developing applications
• Decisions
• Conditions and loops
• Arithmetic operators
• Programming applications in Engineering

Evaluation Methods

• Assignments
• Labs
• Quizzes
• Final Exam

Introduction to Programming

• A programming language enables humans to provide instructions describing actions for a computer
• The processor uses machine code
• Binary data, consisting of 0s and 1s, reaches the processor
• Machine code is generally difficult for humans to understand
• There is a need for intermediary languages that humans can understand
• Compilers and interpreters translate code into machine code for the computer to process
• Programming languages can be classified based on levels of abstraction, how codes are translated to machine code, and programming paradigm

Levels of Abstraction

• Low-level languages have very low abstraction, closer to machine level.
• High-level languages have a high level of abstraction, closer to human understanding.
• Low-level languages are difficult for humans and machine dependent and include machine and assembly language
• High-level languages require translation by a compiler or interpreter and Machine Independent languages, like C++, VB and C#

Code Translation

• Languages can be classified as Compiled, Interpreted, or Intermediary
• ADA is a compiled language for real-time applications
• BASIC is an interpreted language for educational purposes
• C is a compiled language for system programming
• C++ is a compiled language for system object programming
• Cobol is a compiled language for management
• Fortran is a compiled language for calculation
• Java is an intermediary language for internet-oriented programming
• MATLAB is an interpreted language for mathematical calculations

Programming Paradigm

• Languages can be classified as Object-oriented, Imperative or procedural, Concurrent, Functional, or Scripting

C#

• This course will focus on computer programming using C#
• C# is simple, modern, and object-oriented
• C# is type-safe, interoperable, scalable, updateable and component-oriented
• Basic C# programs consist of a namespace declaration, a class, the Main method, statements and expressions, and comments

C# program structure

• using System;
• namespace HelloWorldApplication
• Inside the namespace is the class, class HelloWorld
• Inside the class is the main method, static void Main(string[] args)
• Inside the main method is where you make comments /* my first program in C# */
• And statements, Console.Writeline("Hello World");
• C# is case sensitive
• C# program execution starts at the Main method
• All C# expressions and statements must end with a semicolon (;)
• File names can be different from the class name

Data Types

• Data types specify the type of information stored in a variable's allocated memory space
• C# requires specifying the data type of a variable during declaration so that it is strongly typed, and the compiler is aware of what type of data is expected
• Grade point average is often a double
• Age is often an int
• Full name is often a string
• Final grade is often a char
• Data types are divided into value types, reference types, and pointer types

Data Variables

• Data variables are memory locations that hold data that can be changed during project execution
• Every variable has a type that determines what values can be stored
• They are used for storing values, calculating, and reusability

Constants

• Constants are memory locations that hold data that cannot be changed during project execution
• Use the keyword CONST, and are given a name, a data type, and a value
• const type identifier = expression;

Declaring Variables

• Declaring a variable or named constant reserves a memory area and assigns it an identifier name
• Identifier names are specified according to recommended naming conventions
• The syntax for declaring a variable is DataType VariableName;
• Rules for creating an identifier include that they use a combination of alphabetic characters (a-z and A-Z), numeric digits (0-9), and the underscore, and that the first character be alphabetic
• There should be no embedded spaces and identifiers must not use keywords
• Use the case of the character to your advantage, be descriptive with meaningful names, and follow naming conventions or general naming conventions
• int studentCount; // number of students in the class

Assignment

• Assignment is used to change the value of a variable
• The assignment operator is (=)
• The syntax is variable = expression;
• Expressions can be another variable, a compatible literal value, a mathematical equation, a call to a method that returns a compatible value, or A combination of one or more items in this list
• 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;

Operators

• An operator is a symbol that instructs the compiler to perform specific mathematical or logical manipulations
• C# has a rich set of built-in operators
• C# uses arithmetic, relational, logical, and assignment operators

Arithmetic Operations

• The simplest form of an assignment statement is resultVariable = operand1 operator operand2;
• Readability is improved by using a space before and after every operator
• Supported arithmetic operators:
  • + Adds two operands: A + B = 30
  • - Subtracts the second operand from the first: A - B = -10
  • * Multiplies both operands: A * B = 200
  • / Divides numerator by de-numerator: B / A = 2
  • % Modulus Operator and remainder after integer division: B % A = 0
  • ++ Increment operator increases integer value by one: A++ = 11
  • -- Decrement operator decreases integer value by one: A-- = 9

Mathematical Functions

• Common C# math functions include:
  • sqrt() Computes square root, e.g., sqrt(16)=4
  • pow() Raise one value to a power, e.g., pow(2,3)=8
  • log() Compute natural logarithm, e.g., log(5.5)=1.704748
  • log10() Compute common logarithm, e.g., log10(1000)=3
  • modf() Break into fractional and integral parts, e.g., modf(3.14)=3.00+0.14
  • cos() Computes cosine of an angle of x radians, e.g., cos(60*PI/180)=0.5 (i.e., the cos of 60 degrees is 0.5)

Increment and Decrement Operations

• Increment/Decrement operations:
  • num++; increment // num = num + 1;
  • --valuel; decrement // value = value – 1;
• There is preincrement/predecrement versus post
  • int num = 100;
  • messagebox.show (num++); // Displays 100
  • messagebox.show(num); // Display 101
  • messagebox.show(++num); // Displays 102

Relational Operators

• Relational operators compare two values.
• The relational operators supported by C# include:
  • == Checks if the values of two operands are equal or not; if yes, then the condition becomes true. (A == B) is not true.
  • != Checks if the values of two operands are equal or not; if values are not equal, then the condition becomes true. (A != B) is true.
  • > Checks if the value of the left operand is greater than the value of the right operand; if yes, then the condition becomes true. (A > B) is not true.
  • < Check if the value of the left operand is less than the value of the right operand; if yes, then the condition becomes true. (A < B) is true.
  • >= Checks if the value of left operand is greater than or equal to the value of the right operand; if yes, then the condition becomes true. (A >= B) is not true.
  • <= Checks if the value of the left operand is less than or equal to the value of the right operand; if yes, then condition becomes true. (A <= B) is true.

Logical Operators

• Logical operators take Boolean values as operands and returns a Boolean value.
• The logical operators supported by C#:
  • && Called Logical AND operator. If both the operands are non-zero, then the condition becomes true. (A && B) is false.
  • || Called Logical OR Operator. If any of the two operands is non-zero, then the condition becomes true. (A || B) is true.
  • ! Called Logical NOT Operator. Use to reverse the logical state of its operand. If the condition is true, then the Logical NOT operator will make it false. !(A && B) is true.

Assignment Operators

• Assignment operators are used to assign values to variables.
• The assignment operators supported by C# :
  • = Simple assignment operator. Assigns values from the right-side operands to the left-side operand. C = A + B assigns value of A + B into C
  • += Add AND assignment operator. It adds the right operand to the left operand and assigns the result to left operand. C += A is equivalent to C = C + A
  • -= Subtract AND assignment operator. It subtracts right operand from the left operand and assigns the result to left operand. C -= A is equivalent to C = C - A
  • *= Multiply AND assignment operator. It multiplies the right operand with the left operand and assigns the result to left operand. C *= A is equivalent to C = C * A
  • /= Divide AND assignment operator. It divides the left operand with the right operand and assigns the result to left operand. C /= A is equivalent to C = C / A
  • %= Modulus AND assignment operator. It takes modulus using two operands and assigns the result to left operand. C %= A is equivalent to C = C % A