CS130 Introduction to Programming with VB 6.0
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Transcript of CS130 Introduction to Programming with VB 6.0
CS130 Introduction to Programming with VB 6.0
Fall 2001
Computer System
• Computer hardware• Computer software• Users + computer professionals
Hardware
• Computer hardware– Central Processing Unit (CPU): interprets and executes
instructions– Main memory (RAM): stores programs/data that are
currently being executed/processed; volatile.– Secondary memory (floppy disk, hard disk, CD, DVD):
mass backup storage; non-volatile.– Input devices: keyboard, scanners, etc.– Output devices: printers, monitors, etc.
Software
• Software = program(s); a program is a list of instructions (coded in a particular programming language) that directs the hardware to perform a specific data processing task.
Two types of software
• Systems software: performs system-oriented tasks such as backing up files; typical system software includes the operating system such as MS Windows and compilers
• Applications software: performs user-oriented tacks such as wordprocessing; typical applications software includes wordprocessors, Power-point, etc.
Three-levels of Computer Languages
• Low-level machine language: 0's and 1's• Intermediate assembler languages: mnemonics;
needs translator known as assembler.• High-level procedural languages: needs translators
known as compilers; Visual Basic which will be taught in this class is a popular HLL.
• Natural or spoken language: an ideal; hard to implement due to ambiguities
Visual Basic a brief history
• BASIC: Beginners All-purpose Symbolic Instruction Code, implemented in the 1960s; easily to learn/use; handles only textual data.
• Visual BASIC: evolved from BASIC, capable of handling both graphical and textual materials; object-oriented and event-driven language.
Program development life cycle (PDLC)
Flowchart symbols: tools for algorithm development
Structured programming (top-down chart or hierarchy chart or hierarchical input process output or HIPO)
Basic construct (building block) of a program
Basic construct (building block) of a program
Basic construct (building block) of a program
Basic construct (building block) of a program
Basic construct (building block) of a program
Example: sales commission computation for female and male salespersons for a company
Object-oriented programming: concepts of class, sub-class, super-class, inheritance, objects (instances)
Unified Modeling Language (UML): describing and documenting an OO system
Event-driven programming paradigm