Lecture 3: loops

• booleans and operators
• loops

booleans

• type bool
• implicit conversion (nonzero is true!)
• relational/comparison operators (watch out for = and ==)
• boolean operators (and,or,not)

loops

• iteration in Scheme: factorial
• iteration as updating an environment
• while loops in C
• tail recursion
• factorial in C
• prime number test

other kinds of loops

• for (repeat a code -- handles update for you)
• do while
• what loop do I use?

syntax gotcha: curly braces

• if { s1; s2; } vs. if s1; s2;
• same for other blocks of code