The Boolean (bool) Datatype

• We will next learn how to allow our program to make simple yes/no decisions,
• But before that, we need a datatype to represent yes and no.
• This is the bool datatype.
• The bool datatype is a c++ datatype, did not exist in c
• Range: true, false
  • As a carryover from c, 0 is false and anything else is true.
  • you will frequently see people use 0 and 1 for false and true.
  • Any c functions that deal with booleans will return int
  • See isalpha for example.
• Operations
  • and, or, not
  • &&, ||, ! are equivalent
  • &, | are NOT
  • Input and output are not supported
• This is actually a subtype of the integers.
• There are a number of operators (6) which produce booleans
  • exp1 == exp2, note two = signs.
  • exp1 != exp2
  • exp1 < exp2
  • exp1 <= exp2
  • exp1 > exp2
  • exp1 >= exp2
• Integers and characters are easy with these expressions.
• Strings:
  • compare the first character, then second ....
  • If one string ends then it is less than the other.
  • ASCII order
• Floats are tough
  • x == y is problematic
  • fabs(x-y) < ACCURACY_LEVEL is better.
• We don't always store boolean values, but we need to know the type.
• Write a program that prints the and table
• and.cpp