C Programming for Engineers Bit Manipulation ICEN 360 Spring 2017 - - PowerPoint PPT Presentation

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C Programming for Engineers Bit Manipulation

ICEN 360– Spring 2017

• Prof. Dola Saha

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Bitwise Operation

Ø Computers represent all data internally as sequences of

bits.

Ø Each bit can assume the value 0 or the value 1. Ø The bitwise operators are used to manipulate the bits of

integral operands both signed and unsigned.

Ø Unsigned integers are normally used with the bitwise

• perators.

Ø Bitwise manipulations are machine dependent.

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Bitwise Operator

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Bitwise Operation Example

00001101 11110010 00011010 n=13 ~n n << 1

Lost 0 0 Inserted

01101000 n << 3

Lost three 0s Inserted three 0’s

00000001 n >> 3

Inserted three 0s 101 Lost

00001101 00001101 00001101

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Bitwise Operation Example

00000101 01011101 01011000 00001101 01010101 00001101 01010101 00001101 01010101

n m n&m n m n|m n m n^m

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Display Bits Example (1)

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Display Bits Example (2)

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Bitwise Operation Example Code (1)

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Bitwise Operation Example Code (2)

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Bitwise Operation Example Code (3)

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Bitwise Operation Example Code (4)

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Bitwise Operation Example Code Output

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Bitwise Operation Application:

source port # dest port #

32 bits

application data (variable length) sequence number acknowledgement number

receive window Urg data pointer checksum

F S R P A U

head Len (4) not used

• ptions (variable length)

URG: urgent data (generally not used) ACK: ACK # valid PSH: push data now (generally not used) RST, SYN, FIN: connection estab (setup, teardown commands) # bytes rcvr willing to accept counting by bytes

• f data

(not segments!) Internet checksum (as in UDP)

TCP segment structure

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Multiply and Divide by Bitwise Operation

Ø Left Shift § Multiply Ø Right Shift § Divide

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Revisiting Classwork Assignment

Ø Write a program to generate data for N students. Use

structure to create numeric ID and points (max 100) as 2 separate members of the structure. Randomly generate data for N students. Display both the ID and the points of the student who has received highest point. Write three separate functions to complete the program:

• 1. generateStudentData(), input is array of students
• 2. printStudentInfo(), input is a single student
• 3. getTopStudent(), input is array of students and output is a

single student