CIS 3142 Advice — Chapter 9

[1] Don't declare a variable until you have a value to initialize it with; §9.3, §9.4.3, §9.5.2.

earlier languages used to require all local declarations appear before the first executable statement

[2] Prefer a switch-statement to an if-statement when there is a choice; §9.4.2.

i.e., when comparing an object (suitable for the variable of a switch against a sequence of values
Consider the following two if sequences:
```
if (x < y)
	if (x < z)
		min = x;
	else
		min = z;
else
	if (y < z)
		min = y;
	else
		min = z;
				
```
```
if (choice == 1)
	handleDeposit();
else if (choice == 2)
	handleWithdrawal();
else if (choice == 3)
	handleBalanceInquiry();
				
```
- in the first sequence, the conditions being tested are semantically unrelated, and deal with difference pairs of variables/values.
  - The indentation reflects this, the x < z condition is indented because it is subsidiary to the x < z condition
- If the second sequence, the conditions are all semantically related, in each case, choice is being compared against a value
  - This is the typical scenario that calls out for a switch

[3] Prefer a range-for-statement to a for-statement when there is a choice; §9.5.1.

[4] Prefer a for-statement to a while-statement when there is an obvious loop variable; §9.5.2.

when a loop variable is present, the for statement provides a more structured way of handling it than the corresponding while

[5] Prefer a while-statement to a for-statement when there is no obvious loop variable; §9.5.3.

the main advantage of the for loop is the structured haling of the loop variable; without it, the while loop provides more straightforward code

the body if the 'do-while' loop is always executed at least one, and is thus error-prone in that it doesn't handle empty loop cases

i.e., a comment should be a high-level statement of what the goes is supposed to do, whereas the code itself states what (or how) it actually does it
a corollary of this is probably that a comment should subsume several statements, rather than a single one

CISC 3142
Programming Paradigms in C++
Part II: Basic Facilities
Chapter 9 - Statements