Introduction to C Language . BCA sem-1 notes

1. Basic Concepts of Programming Languages

Programming languages are tools used to communicate with computers. Key concepts include:

• Syntax: The rules that define the structure of a language (e.g., grammar, symbols).
• Semantics: The meaning of the statements or expressions within a program.
• Pragmatics: The practical usage of a language in real-world scenarios.

Core Elements:

1. Variables: Storage for data values.
2. Control Structures: Constructs like loops (for, while) and conditionals (if-else).
3. Data Types: Define types of data (e.g., integers, strings).
4. Functions: Modular blocks of reusable code.
5. Objects and Classes: For object-oriented programming (OOP).

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2. Programming Domains

Programming languages are often designed to cater to specific application domains:

1. Scientific Applications: Languages like Fortran and MATLAB focus on numerical computations.
2. Business Applications: COBOL excels in financial and record-keeping systems.
3. Web Development: HTML, CSS, JavaScript, and Python are common here.
4. Systems Programming: C and Rust are popular for operating systems and hardware interfaces.
5. Artificial Intelligence: Python, Lisp, and Prolog dominate AI and machine learning.

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Also Read: what is Iteration/Loops in C 

3. Language Evaluation Criteria

Programming languages are evaluated based on several factors:

1. Readability: How easy it is to understand the code.
2. Writability: How easily a programmer can write code to solve problems.
3. Reliability: Ensuring the language can produce error-free results.
4. Cost: Includes development time, performance efficiency, and maintenance.
5. Portability: The ability to run on different platforms.
6. Expressiveness: How concisely ideas can be expressed in the language.

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4. Language Categories

Programming languages are grouped based on paradigms and abstraction levels:

1. Imperative Languages: Focus on how tasks are performed (e.g., C, Python).
2. Functional Languages: Based on mathematical functions (e.g., Haskell, Lisp).
3. Object-Oriented Languages (OOP): Emphasize objects and inheritance (e.g., Java, C++).
4. Logic-Based Languages: Focus on formal logic (e.g., Prolog).
5. Scripting Languages: Simplify automating tasks (e.g., JavaScript, Python).

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5. Evolution of Major Programming Languages

• 1940s-1950s: Assembly and machine languages.
• 1957: Fortran – First high-level programming language.
• 1960: COBOL – Business applications.
• 1970s:
  • C – System programming.
  • Pascal – Educational purposes.
• 1980s: C++ – Introduction of OOP.
• 1990s:
  • Java – Platform independence.
  • Python – Simplicity and versatility.
• 2000s and beyond:
  • Modern scripting and web technologies (JavaScript, Ruby).
  • AI and ML-focused languages (Python, R).

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6. Describing Syntax and Semantics

1. Syntax: Deals with structure.
   • Example: A syntax rule for assignment: variable = expression;
2. Semantics: Defines what the syntax means.
   • Example: x = x + 1 means "increment the value of x by 1."

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7. Formal Methods of Describing Syntax

1. Backus-Naur Form (BNF): A notation for defining formal grammar.
2. Syntax Diagrams: Graphical representation of syntax.
3. Parsing: The process of analyzing syntax structure.

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8. Pseudo Code

Pseudo code is an informal way of designing algorithms using simple English-like statements, without syntax rules.

Example:

Start
  Input: two numbers, A and B
  Output: Sum of A and B
  Process: Add A and B
End

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9. Design of Algorithm & Flowchart

• Algorithm: A step-by-step procedure to solve a problem. Example: Sorting an array.
• Flowchart: A visual representation of an algorithm using symbols like:
  • Oval: Start/End.
  • Rectangle: Process.
  • Diamond: Decision.
  • Arrow: Flow direction.

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