decomposition (slides)

CSc 110 - decomposition

Program decomposition

Program decomposition refers to the process of breaking down a complex program into smaller, more manageable, and understandable parts or components.

It avoids unnecessary common code and improves the structural quality of code.

Print a classic guitar

print("      ___")
print("    o|* *|o")
print("    o|* *|o")
print("    o|* *|o")
print("     \===/")
print("      |||")
print("      |||")
print("   ___|||___")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("|     |||     |")
print(" \   (|||)   /")
print("  |   |||   |")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("/     |||     \ ")
print("|    [===]    |")
print(" \           /")
print("  '.       .'")
print("   '-------'")

Print a retro head guitar

print("     ._-_.")
print("    +|\G/|+")
print("    +|\./|+")
print("    +|\./|+")
print("     \===/")
print("      |||")
print("      |||")
print("   ___|||___")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("|     |||     |")
print(" \   (|||)   /")
print("  |   |||   |")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("/     |||     \ ")
print("|    [===]    |")
print(" \           /")
print("  '.       .'")
print("   '-------'")

Print a long neck guitar

print("      ___")
print("    o|* *|o")
print("    o|* *|o")
print("    o|* *|o")
print("     \===/")
print("      |||")
print("      |||")
print("      |||")
print("      |||")
print("   ___|||___")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("|     |||     |")
print(" \   (|||)   /")
print("  |   |||   |")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("/     |||     \ ")
print("|    [===]    |")
print(" \           /")
print("  '.       .'")
print("   '-------'")

Class activity one

Compare different types of guitar, write your answers:

• which parts of code are the same?

• which parts of code are different?

Classic guitar vs. Retro head guitar

• which parts of code are the same?

  • the neck and the body

• which parts of code are different?

  • the head: line 1-4

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()

def print_retro_guitar():
    print_retro_head()
    print_neck()
    print_body()

Classic guitar vs. Long neck guitar

• which parts of code are the same?

  • the head and the body

• which parts of code are different?

  • the neck

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()
    
def print_long_guitar():
    print_head()
    print_neck()
    print_neck()
    print_body()

Decompose a program into functions

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()

def print_retro_guitar():
    print_retro_head()
    print_neck()
    print_body()
    
def print_long_guitar():
    print_head()
    print_neck()
    print_neck()
    print_body()

def main():
    print_classic_guitar() # print classic guitar
    print_retro_guitar() # print retro head guitar
    print_long_guitar() # print long neck guitar

main()

Class activity two

Read the code for classic guitar, write your asnwers:

• which lines of code are the same?

  • in the head:

  • in the neck:

  • in the body:

Print a classic guitar

print("      ___")
print("    o|* *|o")
print("    o|* *|o")
print("    o|* *|o")
print("     \===/")
print("      |||")
print("      |||")
print("   ___|||___")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("|     |||     |")
print(" \   (|||)   /")
print("  |   |||   |")
print("  /   |||   \ ")
print(" /    |||    \ ")
print("/     |||     \ ")
print("|    [===]    |")
print(" \           /")
print("  '.       .'")
print("   '-------'")

Class activity two – answers

Read the code for classic guitar, answer the questions:

• which lines of code are the same?

  • in the head: line 2 - 4

  • in the neck: line 6 - 7

  • in the body: line 9 - 10 and line 14 - 15

Class activity two – answers

print("      ___")
print("    o|* *|o") # head
print("    o|* *|o") # head
print("    o|* *|o") # head
print("     \===/")
print("      |||") # neck
print("      |||") # neck
print("   ___|||___")
print("  /   |||   \ ") # body
print(" /    |||    \ ") # body
print("|     |||     |")
print(" \   (|||)   /")
print("  |   |||   |")
print("  /   |||   \ ") # body
print(" /    |||    \ ") # body
print("/     |||     \ ")
print("|    [===]    |")
print(" \           /")
print("  '.       .'")
print("   '-------'")

Write functions

Write functions print_head, print_neck, and print_body:

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()

def print_long_guitar():
    print_head()
    print_neck()
    print_neck()
    print_body()

def main():
    print_classic_guitar() # print classic guitar
    print_long_guitar() # print long neck guitar

main()

Write functions – answers

def print_head():
    print("      ___")
    print("    o|* *|o")
    print("    o|* *|o")
    print("    o|* *|o")
    print("     \===/")

def print_neck():
    print("      |||" + "\n" + "      |||")
    
def print_body():
    print("   ___|||___")
    print("  /   |||   \ ")
    print(" /    |||    \ ")
    print("|     |||     |")
    print(" \   (|||)   /")
    print("  |   |||   |")
    print("  /   |||   \ ")
    print(" /    |||    \ ")
    print("/     |||     \ ")
    print("|    [===]    |")
    print(" \           /")
    print("  '.       .'")
    print("   '-------'")

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()

def print_long_guitar():
    print_head()
    print_neck()
    print_neck()
    print_body()

def main():
    print_classic_guitar() # print classic guitar
    print_long_guitar() # print long neck guitar

main()

      ___
    o|* *|o
    o|* *|o
    o|* *|o
     \===/
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'
      ___
    o|* *|o
    o|* *|o
    o|* *|o
     \===/
      |||
      |||
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'

Write functions – improved answers

def print_head():
    print("      ___")
    pattern = "    o|* *|o"
    print(pattern)
    print(pattern)
    print(pattern)
    print("     \===/")

def print_neck():
    print("      |||" + "\n" + "      |||")
    
def print_body():
    print("   ___|||___")
    pattern = "  /   |||   \ " + "\n" + " /    |||    \ " 
    print(pattern)
    print("|     |||     |")
    print(" \   (|||)   /")
    print("  |   |||   |")
    print(pattern)
    print("/     |||     \ ")
    print("|    [===]    |")
    print(" \           /")
    print("  '.       .'")
    print("   '-------'")

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()

def print_long_guitar():
    print_head()
    print_neck()
    print_neck()
    print_body()

def main():
    print_classic_guitar() # print classic guitar
    print_long_guitar() # print long neck guitar

main()

      ___
    o|* *|o
    o|* *|o
    o|* *|o
     \===/
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'
      ___
    o|* *|o
    o|* *|o
    o|* *|o
     \===/
      |||
      |||
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'

Add function print_retro_head

def print_head():
    print("      ___")
    pattern = "    o|* *|o"
    print(pattern)
    print(pattern)
    print(pattern)
    print("     \===/")

def print_retro_head():
    print("     ._-_.")
    print("    +|\G/|+")
    pattern = "    +|\./|+"
    print(pattern)
    print(pattern)
    print("     \===/")

def print_neck():
    print("      |||" + "\n" + "      |||")
    
def print_body():
    print("   ___|||___")
    pattern = "  /   |||   \ " + "\n" + " /    |||    \ " 
    print(pattern)
    print("|     |||     |")
    print(" \   (|||)   /")
    print("  |   |||   |")
    print(pattern)
    print("/     |||     \ ")
    print("|    [===]    |")
    print(" \           /")
    print("  '.       .'")
    print("   '-------'")

def print_classic_guitar():
    print_head()
    print_neck()
    print_body()

def print_retro_guitar():
    print_retro_head()
    print_neck()
    print_body()
    
def print_long_guitar():
    print_head()
    print_neck()
    print_neck()
    print_body()

def main():
    print_classic_guitar() # print classic guitar
    print_retro_guitar() # print retro head guitar
    print_long_guitar() # print long neck guitar

main()

      ___
    o|* *|o
    o|* *|o
    o|* *|o
     \===/
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'
     ._-_.
    +|\G/|+
    +|\./|+
    +|\./|+
     \===/
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'
      ___
    o|* *|o
    o|* *|o
    o|* *|o
     \===/
      |||
      |||
      |||
      |||
   ___|||___
  /   |||   \ 
 /    |||    \ 
|     |||     |
 \   (|||)   /
  |   |||   |
  /   |||   \ 
 /    |||    \ 
/     |||     \ 
|    [===]    |
 \           /
  '.       .'
   '-------'

Discussion

Download and run old guitar file and new guitar file:

• Which version is more readable?

• Why it is better?