Assignment%201%20Debrief

1
Assignment 1 Debrief

• Andy Wang
• Data Structures, Algorithms, and Generic
  Programming

2
makefile

• Reasons for using a makefile
• Standard practice in the UNIX world
• Describe dependencies among files
• Easy to rename files, change include paths, and
  so on
• Automatically generate header file dependencies

3
A Simple makefile

• all libbit.a sieve.x
• libbit.a bitvector.o
• ar cr libbit.a bitvector.o
• ranlib libbit.o
• sieve.x main.o sieve.o libbit.a
• g -g ansi Wall main.o sieve.o I/usr/include
  L. lbit o sieve.x
• bitvector.o bitvector.cpp bitvector.h
• g -g ansi Wall I/usr/include c o
  bitvector.o bitvector.cpp
• sieve.o sieve.cpp bitvector.h sieve.h
• g -g ansi Wall I/usr/include c o sieve.o
  sieve.cpp
• main.o main.cpp sieve.h
• g -g ansi Wall I/usr/include c o main.o
  main.cpp
• clean
• rm f .o libbit.a sieve.x core .bak

4
To ease changing flags

• FLAGS -g ansi Wall -O
• all libbit.a sieve.x
• libbit.a bitvector.o
• ar cr libbit.a bitvector.o
• ranlib libbit.o
• sieve.x main.o sieve.o libbit.a
• g (FLAGS) main.o sieve.o I/usr/include L.
  lbit o sieve.x
• bitvector.o bitvector.cpp bitvector.h
• g (FLAGS) I/usr/include c o bitvector.o
  bitvector.cpp
• sieve.o sieve.cpp bitvector.h sieve.h
• g (FLAGS) I/usr/include c o sieve.o
  sieve.cpp
• main.o main.cpp sieve.h
• g (FLAGS) I/usr/include c o main.o
  main.cpp
• clean
• rm f .o libbit.a sieve.x core .bak

5
make depend

• FLAGS -g ansi Wall -O
• all libbit.a sieve.x
• libbit.a bitvector.o
• ar cr libbit.a bitvector.o
• ranlib libbit.o
• sieve.x main.o sieve.o libbit.a
• g (FLAGS) main.o sieve.o I/usr/include L.
  lbit o sieve.x
• bitvector.o bitvector.cpp bitvector.h
• g (FLAGS) I/usr/include c o bitvector.o
  bitvector.cpp
• sieve.o sieve.cpp bitvector.h sieve.h
• g (FLAGS) I/usr/include c o sieve.o
  sieve.cpp
• main.o main.cpp sieve.h
• g (FLAGS) I/usr/include c o main.o
  main.cpp
• clean
• rm f .o libbit.a sieve.x core .bak
• depend
• makedepend -- (FLAGS) I/usr/include
  bitvector.cpp \
• sieve.cpp main.cpp bitvector.h sieve.h
• DO NOT DELETE THIS LINE makedepend depends on
  it.

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Systematic Conversion

• FLAGS -g ansi Wall -O
• all libbit.a sieve.x
• libbit.a bitvector.o
• ar cr libbit.a bitvector.o
• ranlib libbit.o
• sieve.x main.o sieve.o libbit.a
• g (FLAGS) main.o sieve.o I/usr/include L.
  lbit o sieve.x
• .cpp.o
• g (FLAGS) I/usr/include c o .o .cpp
• clean
• rm f .o libbit.a sieve.x core .bak
• depend
• makedepend -- (FLAGS) I/usr/include
  bitvector.cpp \
• sieve.cpp main.cpp bitvector.h sieve.h
• DO NOT DELETE THIS LINE makedepend depends on
  it.

7
To ease changing include paths

• INC -I/usr/include
• FLAGS -g ansi Wall -O
• all libbit.a sieve.x
• libbit.a bitvector.o
• ar cr libbit.a bitvector.o
• ranlib libbit.o
• sieve.x main.o sieve.o libbit.a
• g (FLAGS) main.o sieve.o (INC) L. lbit o
  sieve.x
• .cpp.o
• g (FLAGS) (INC) c o .o .cpp
• clean
• rm f .o libbit.a sieve.x core .bak
• depend
• makedepend -- (FLAGS) (INC) bitvector.cpp
  sieve.cpp main.cpp \ bitvector.h sieve.h
• DO NOT DELETE THIS LINE makedepend depends on
  it.

8
BitVector
70
158
23.16
10010101 00101001 10010010
unsigned char array
array0
array1
array2
ByteNumber(17) 2
Mask(17) 00000010(2)
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ByteNumber(bit_index)

• Bad name
• Should be BasictypeArrayIndexNumber()
• Goal
• Return the index of the Basictype array that
  holds the bit

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Set()

• Goal
• 10100010010 ? 1111..11111
• Arrayj 0x01 // use only 1 out of n bits
• Arrayj 0xFF // OK only for unsigned char
• Arrayj 0xFFFFFFFF
• Arrayj 0x0

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Set(bit_index)

• Goal
• 10100010010 ? 10110010010
• To set a bit to 1
• 0 1 ? 1
• 1 1 ? 1
• To preserve remaining bits
• 0 0 ? 0
• 1 0 ? 1

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Set(bit_index)

• 10100010010
• 00010000000
• 10110010010
• ArrayByteNumber(bit_index) Mask(bit_index)

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Unset()

• Goal
• 10100010010 ? 00000.000000
• 0 0 0
• 1 0 0
• Arrayj 0x0
• 0 0 0
• 1 1 0
• Arrayj Arrayj Arrayj

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A Neat Trick

• A 11001010
• B 00100101
• A A B
• B A B
• A A B

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Unset(bit_index)

• Goal
• 10100010010 ? 10000010010
• To set a bit to 0
• 0 0 ? 0
• 1 0 ? 0
• To preserve remaining bits
• 0 1 ? 0
• 1 1 ? 1

16
Unset(bit_index)

• 10100010010
• 11011111111
• 10000010010
• ArrayByteNumber(bit_index) Mask(bit_index)

17
Flip()

• Goal
• 10100010010 ? 01011.101101
• 1 0
• 0 1
• Arrayj Arrayj
• 1 1 0
• 0 1 1
• Arrayj Arrayj 0x0

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Flip(bit_index)

• Goal
• 10100010010 ? 10101010010
• if (Test(bit_number))
• Unset(bit_number)
• else
• Set(bit_number)

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Common Errors

• Basictype vector vs. bit vector
• ! vs.
• vs.
• Mask() vs. BitVectorMask()
• include ltbitvector.hgt vs. include bitvector.h
  

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Common Errors

• Foo()
• vs.
• Foo()

Personally, I prefer Foo()