Programming
languages allow several types of values: numeric, strings of letters,
Boolean
•numbers: 1 0
-433 6.022e+23 .01
•not
numbers: 1,000 106 5%
7±2
•strings: "abc"
'efg' " "
"B&B's"
""
•not
strings: ' '<tab>'
"a ' "\"
•Boolean: true
false
•not
Boolean: T F yes no