CSA 2.6-2.11 Vocab

CSA Runestone 2.6-2.11 Vocab

De Morgan's Law

Can be applied to Boolean expressions to create equivalent ones:

!(a && b) is equivalent to !a || !b

!(a || b) is equivalent to !a && !b

Negation

A negated expression with a relational operator can be simplified by flipping the relational operator to its opposite sign.

!(c == d) is equivalent to c != d

!(c != d) is equivalent to c == d

!(c < d) is equivalent to c >= d

!(c > d) is equivalent to c <= d

!(c <= d) is equivalent to c > d

!(c >= d) is equivalent to c < d

Aliases

When two object references reference the same object

While Loop

A type of iterative statement. The Boolean expression is evaluated before each iteration of the loop body, including the first. When the expression evaluates to true, the loop body is executed. This continues until the Boolean expression evaluates to false, whereupon the iteration terminates.

Loop Control Variable

Used in the boolean condition of the loop

Infinite Loop

occurs when the Boolean expression in an iterative statement always evaluates to true

Off by One Error

occur when the iteration statement loops one time too many or one time too few

Input Controlled Loops

Use a sentinel value that is input by the user like “bye” or -1 as the condition for the loop to stop

For Loop

Type of iterative statement. There are three parts: the initialization (of the loop control variable or counter), the Boolean expression (testing the loop variable), and the update (to change the loop variable).

Accumulator Pattern

An algorithm that involves storing and updating an accumulator value within a loop, for example to compute a sum or average of a set of values.

int length()

returns the number of characters in a String object

int indexOf(String str)

returns the index of the first occurrence of str or -1 if str is not found

String substring(int from, int to)

returns the substring beginning at index from and ending at index (to – 1). Note that s.substring(i,i+1) returns the character at index i

String substring(int from)

returns substring(from, length())

Nested Iteration Statements

Iteration statements that appear in the body of another iteration statement. When a loop is nested inside another loop, the inner loop must complete all its iterations before the outer loop can continue.