| Story Problems | Debugging |
| List of Story Problems | Anglish Statements |
| List of Formulas used in Story Problems | Anglish Features |
The alternative program for the net wages problem is the single statement:
net wages = rate X time - rate X time X percent/100
An alternative form of this statement can be obtained by factoring.
Producing:
net wages = rate X time X (1 - percent/100)
Either form is acceptable. In general, factoring may improve the
efficiency of the computation. In this case, the first form
requires three multiplications, a division and a subtraction. The
factored form requires only two multiplications, a division and a
subtraction. In a computer, the total number of arithmetic
operations determines the amount of work the computer must do.
Therefore, the second form is more efficient.
The sequential program corresponding to the factored form is:
net percent = 100 - percent;
net wages = rate X time X (net percent/100);
The sequential form requires that the programmer use a new variable
name (i.e. net percent). Both the alternative and the sequential
alternative forms use the same number of arithmetic operations.
The sequential form, however, identifies "net percent" as a key
variable. That is, problems of this type are more efficient if
stated with the net percent of take home pay instead of with the
percent of deductions. Frequently, the factored sequential form
provides insight into the basic underlying structure of the
problem.
The plural data class.