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Bits and Bytes

Bits and Bytes. And why we have to care in VB!. All computer storage is organized into bytes. Think of each byte as a little storage bin Each byte is made up of 8 bits Each bit is an electronic circuit that is either on or off (off = 0, on = 1)

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Bits and Bytes

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  1. Bits and Bytes And why we have to care in VB!

  2. All computer storage is organized into bytes • Think of each byte as a little storage bin • Each byte is made up of 8 bits • Each bit is an electronic circuit that is either on or off (off = 0, on = 1) • A specific sequence of 0’s and 1’s in a byte is called a bit pattern

  3. What kinds of information do you store on your computer? • numerical values (binary number system) • text/character data (ASCII or Unicode) • program instructions (machine language) • images (jpg, gif, tiff, bmp, wmf, etc.) • video (mp4, mov, avi, wmv, etc.) • music (mp3, wav, wma, au, etc.)

  4. Numerical Values vsStrings (text/characters) 40 Oak St $40

  5. “40 Oak St” is a string It would be stored like this using ASCII codes

  6. The 40 in $40 needs to be a numerical value for arithmetic The numerical value 40 would be stored like this using the binary number system.

  7. Compare: “40” vs 40 The text string “40” The numerical value 40

  8. How do binary numbers work? 8-bit binary number

  9. Converting from Binary to Decimal What is the decimal value of the bit pattern 01101010 ? Simple! Just add up the positional values where the 1’s appear: 64 + 32 + 8 + 2 = 106 So, we say that 011010102 = 106 decimal

  10. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Simple! Just think about money and consider positional values as coins and 151 “cents” as the change we must make. Then “count change” from largest “denomination” to smallest until total value of change is accumulated.

  11. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128

  12. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128

  13. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128

  14. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128 + 16 = 144

  15. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128 + 16 = 144

  16. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128 + 16 + 4 = 148

  17. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128 + 16 + 4 + 2 = 150

  18. Converting from Decimal to Binary How can we represent the decimal value 151 in binary? Running Total: 128 + 16 + 4 + 2 + 1 = 151 So, 151 decimal = 100101112

  19. Compare: “40” vs 40 The text string “40” The numerical value 40

  20. Consider GPA Program Input? Output?

  21. Consider GPA Program Input Output

  22. Bottom Line All input values provided via text boxes on VB forms are stored as text All output values provided placed in labels on VB forms are stored as text HOWEVER To use values in computations for processing in VB, the values must be numeric

  23. Beginning of GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa Note: credithrs, qualpts, and gpa are called variables gpaLbl

  24. Input Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  25. Input Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  26. Input Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  27. Input Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  28. Input Phase GPA Program On Screen Behind the Scenes In memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  29. Processing Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  30. Processing Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  31. Output Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  32. Output Phase GPA Program On Screen Behind the Scenes in Memory (RAM) credithrsTxt credithrs qualptsTxt qualpts gpa gpaLbl

  33. Good News is … • We don’t have to directly handle the nitty-gritty details of converting text to binary for input • We don’t have to directly handle the nitty-gritty details details of converting binary to text for output • Phew!

  34. Not So Good News is … • We do have to explicitly ask VB to do the conversions when necessary

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