1. Branching Constructs Review
what are branching constructs? what type of branching constructs have we studied?
what is a nested if?
what is a multiway if? How does a multiway if relate to a nested if?
what is a switch statement? is it better than a multiway if?
what does break inside switch do?
what is conditional assignment? what construct can be used instead?
what are named constants? why are they needed?
what is a block? what is special about declaring a variable inside a block? what is scope of a variable?
what is a programming idiom?
what is a unary, binary, tertiary operator?

2. Iterative Constructs
while, for, do-while 2

3. Iterative Constructs provide
ability to execute the same code multiple times
three constructs
while statement
do-while statement
for statement

4. The while Statement expression action true false syntax
while (expression)
action
semantics
if expression is true then execute action
repeat this process until expression evaluates to false
action is either a single statement or a block

5. The do-while Statement
syntax do
action
while (expression);
semantics
execute action
if expression is true then execute action again
repeat this process until expression evaluates to false
action is either a single statement or a block
action
true
expression
false

6. The for Statement init_statement syntax for(init_statement;
expression
action
true
false
init_statement
post_statement
syntax
for(init_statement;
expression; post_statement)
action
semantics
execute init_statement
evaluate expression if true
execute action
execute post_statement
repeat
example
for (int i = 0; i < 20; ++i) { cout << "i is " << i << endl; }

7. Break and Continue with Iterative Constructs
break - exits innermost loop
int sum=0;
while(sum < 100) {
int i; cin >> i;
if (i< 0) {
cout << ”found negative number\n”;
break; }
sum +=i;
continue - skip the remaining statements and start a new iteration (evaluate expression)
for (int i = 0; i < 20; ++i) { int intVar;
cin >> intVar;
if(intVar < 0) continue;

8. Nesting of Iterative Constructs
iterative constructs can be nested: one iterative construct may be inside the body of another
example:
for (int i = 0; i < 10; ++i) // outer loop
for (int j = 0; j < 10; ++j) // inner loop
cout << i << j << endl;
what would this code output?
note, there is no need for curly brackets
nesting may be more than two loops deep
for/while/do-while can be mixed in nesting
besides nested loops, loop body may contain other code

9. Iteration
key points
make sure there is a statement that will eventually nullify the iteration criterion (i.e., the loop must stop)
make sure that initialization of any loop counters or iterators is properly performed
have a clear purpose for the loop
document the purpose of the loop and how the body of the loop advances the purpose of the loop