Constants

• Constants are variables with values that the program never changes
• Reasons to use them:
  • improves readability of the source code
  • facilitates easier program modification
• Good programming practice (style):
  • place all constant declarations at the beginning of a program
  • use all CAPITALS for constant names

Example: which code is more clear?

x = 3.14159
y = 1.324
z = 2*x*y

PI = 3.14159
radius = 1.324
circumference = 2*PI*radius