Introduction to Programming Languages

Summary of Previous Lecture

• Need for programming: Computers require instructions to perform tasks, known as programs.
• Types of Programs: System programs, application programs.
• Binary Language: Computers understand binary language (0s and 1s).
• Conversion: Programs in languags like C, C++, Java need to be converted to machine code (0s and 1s) for the CPU to execute.

Levels of Programming Languages

• Categories: Low-level programming languages, High-level programming languages.

Low-Level Programming Languages

1. Machine Language (Machine Code) / Machine Level Language

   • Characteristics: Very close to hardware, machine-oriented, written in binary (0s and 1s).
   • Requirement: Extensive knowledge of CPU architecture and system configuration.
   • Programming: Instructions in machine code are specific to CPU architecture.
   • Advantages: Direct execution by computer, fast execution.
   • Drawbacks: Not readable by humans, machine-dependent, not portable.

2. Assembly Language

   • Characteristics: Uses symbols and numbers (mnemonics) like ADD, SUB, MOV.
   • Conversion: Requires conversion to machine code by an assembler.
   • Advantages: More readable by humans, close to machine language.
   • Drawbacks: Slower than machine language due to need for conversion, still machine-dependent, not portable.

High-Level Programming Languages

• Examples: C, C++, Java, Python, Perl, PHP, Ruby, etc.
• Characteristics: Close to human language, deals with variables, functions, loops, mathematical expressions.
• Advantages: Easier to read, write, understand, and maintain; independent of CPU architecture.
• Drawbacks: Requires conversion to machine code by a compiler or interpreter, slower execution compared to machine language.

Conversion Tools

1. Compiler
   • Takes entire source code and converts it to machine code (object file) before execution.
2. Interpreter
   • Converts and executes source code line by line simultaneously.

Key Concepts

• High-Level Languages: Focus on usability, not optimal program efficiency.
• Portability: Programs are more or less independent of computer system architecture.

Conclusion

• Next lecture will cover writing programs in C language and the execution process behind the scenes.