Programming Concepts PDF

Programming Concepts  Objectives Define computer programing languages Define a computer program Understand the basic terminologies Explore different types of programing languages List different programing language generations Identify different programming...

Programming Concepts  Objectives Define computer programing languages Define a computer program Understand the basic terminologies Explore different types of programing languages List different programing language generations Identify different programming tools Explore different types of programing structures Identify the main steps to solve a problem using programming languages  Programming Languages Programming languages are made up of keywords and grammar rules designed for creating computer instructions Computer Program: a set of instructions that tell the computer how to perform a task. Programmer: a person who writes the program instructions (source code)  Terminologies Keyword/Command – It is a word with a predefined meaning that is reserved by a program that defines commands and specific parameters for that code set. The number of keywords may differ from one language to another. executable vs. non-executable statements – Executable statement: It usually starts with a key word and initiates actions. In other words, it is a description of what and how the program should take an action – Non-Executable statement: It provides info about the nature of the data or about the way the processing is to be done without causing any processing action. Syntax vs. Semantic – Syntax is the grammar rules that are used whenever a program in a computer language is written. (like grammar in the natural language) – Semantics is the function of the command. (like meaning in the natural language)  Terminologies(cont’d) Variable vs. Constant – Variable: it is a memory location and its values are normally changed during the course of program execution. Naming a variable is part of the language syntax. Programmers should follow the language guidelines to name variables. It could be different from one language to others. Variable Declaration : it is to specify a variable’s name and characteristics. Variable Datatype: It is a set of possible values and a set of allowed operations on it. A data type tells the compiler or interpreter how the programmer intends to use the data. – Constant: it is a value that should not be altered by the program during normal execution. Note: if it used as type qualifier then it is used to declare a constant variable like in C language. Variable/constant name should be descriptive  Terminologies (cont’d) File name vs. filename extension – File name: is a framework for naming a file in a way that describes what they contain and how they relate to other files. – Filename extension: It indicates a characteristic of the file contents or its intended use. A filename extension is typically delimited from the filename with period(. ). Example: obj, exe, dat, etc. File types – Source – Object – Executable – Data  Terminologies (cont’d) Interpreter: – A program that translates source code into some efficient intermediate representation or object code and immediately executes that. – It executes one statement at a time. Compiler: – A system program that translates high-level language (source code) to machine language (object code) – It translates the entire source code (statements) at one time. – Assembler: it translates the assembly program (source code) to the object code. Programming Languages Types & Generations  Programming Languages Types Low – Level Language High – Level Language  Programming Language Types Low-level languages typically include commands specific to a particular CPU or microprocessor family. It easy for the machine to understand – Machine Language. Programs are coded in binary (0s and 1s) – Assembly Language. It is a symbolic coded sequence of instructions  Programming Language Types High-level Language: – High-level languages use command words and grammar based on human languages – Languages that are easy to understand and to write by humans using words from the English language. Java C# C and C++  Computer Programming Language Generations First Generation: – Machine Language: It consists of binary instructions (0’s and 1’s) that a computer can understand and respond to directly. Examples: 0101110110111001 Second Generation – Assembly Language: It is a low level programming language using the human readable instructions. It is used in kernels and hardware drives. – Example: Sub, Add, Mov.  Computer Programming Language Generations (cont’d) Third Generation: – Easy-to-remember command words – Procedure Languages: It is a programming language that specifies a series of well- structured steps and procedures within its programming context to compose a program. – These are high-level languages like C, Fortran, and Basic.  Computer Programming Language Generations (cont’d) Fourth Generation: – More closely resembles human language – Object Oriented Language: It is a programming paradigm that represents concepts as "objects" that have data fields and associated methods. – Languages that consist of statements that are similar to statements in the human language. These are used mainly in database programming and scripting. Examples of these languages include Java and Python.  Computer Programming Language Generations (cont’d) Fifth-generation languages Based on a declarative programming paradigm. These are the programming languages that have visual tools to develop a program. Examples of these languages include Prolog.  programming paradigm The programming paradigm refers to a way of conceptualizing and structuring the tasks a computer performs.  Programming Tools An SDK (software development kit) is a collection of language- specific programming tools that enables a programmer to develop applications for a specific computer platform An IDE (integrated development environment) is a type of SDK that packages a set of development tools into a sleek programming application A component is a prewritten module, typically designed to accomplish a specific task An API is a set of application programs or operating system functions that programmers can access from within the programs they create A VDE (visual development environment) provides programmers with tools to build substantial sections of a program  Solving problems using programming language Identify and Understand the problem State/outline the solution Program planning – Algorithm Flowchart Pseudocode Write the program source code Program testing and documentations  Program Planning The problem statement defines certain elements that must be manipulated to achieve a result or a goal You accept assumptions as true to proceed with program planning Known information helps the computer to solve a problem Determine variables & constants  Algorithms Set of steps for carrying out a task that can be written down and implemented Start by recording the steps you take to solve the problem manually Specify how to manipulate information Specify what the algorithm should display as a solution Expressing an Algorithm – Flowchart – Pseudocode Flowchart A flowchart is a graphical representation of solution steps (algorithms and programming logic) for a given problem. Flowchart symbols are the elements you can use to describe the steps involved in a workflow process. Flowchart Symbols - Bing images Example: the following flowchart Start represents a solution to find the largest of two numbers: ( A &B). Read A Read B Yes No It A>B Print A Print B Stop  Pseudocode A Pseudocode is defined as a step-by-step description of an algorithm. It uses the simple English language text as it is intended for human understanding rather than machine reading. Example: Find the largest of two numbers: (A & B)?  Pseudocode Step 1: Start Step 2: Read number a Step 3: Read number b Step 4: if a > b , print a (Compare a and b using greater than operator) Step 5: else print b Step 6: Stop (Output: Largest number between a and b) Writing the // C++ Program to Find Largest of two numbers #include program #include source code void main() { Use the clrscr(); appropriate int a, b, largest; language to write Cout > a >> b; the source code if(a>b) to find the { largest=a; largest of two } numbers. else { Example C, C++, largest=b; C #, Java, etc. } cout