Defined Terms

block Sequence of zero or more statements enclosed in curly braces. A block is a statement, so it can appear anywhere a statement is expected.

break statement Terminates the nearest enclosing loop or switch statement. Execution transfers to the first statement following the terminated loop or switch.

case label Constant expression (§ 2.4.4, p. 65) that follows the keyword case in a switch statement. No two case labels in the same switch statement may have the same value.

catch clause The catch keyword, an exception declaration in parentheses, and a block of statements. The code inside a catch clause does whatever is necessary to handle an exception of the type defined in its exception declaration.

compound statement Synonym for block.

continue statement Terminates the current iteration of the nearest enclosing loop. Execution transfers to the loop condition in a while or do, to the next iteration in a range for, or to the expression in the header of a traditional for loop.

dangling else Colloquial term used to refer to the problem of how to process nested if statements in which there are more ifs than elses. In C++, an else is always paired with the closest preceding unmatched if. Note that curly braces can be used to effectively hide an inner if so that the programmer can control which if a given else should match.

default label case label that matches any otherwise unmatched value computed in the switch expression.

do while statement Like a while, except that the condition is tested at the end of the loop, not the beginning. The statement inside the do is executed at least once.

exception classes Set of classes defined by the standard library to be used to represent errors. Table 5.1 (p. 197) lists the general-purpose exception classes.

exception declaration The declaration in a catch clause. This declaration specifies the type of exceptions the catch can handle.

exception handler Code that deals with an exception raised in another part of the program. Synonym for catch clause.

exception safe Term used to describe programs that behave correctly when exceptions are thrown.

expression statement An expression followed by a semicolon. An expression statement causes the expression to be evaluated.

flow of control Execution path through a program.

for statement Iteration statement that provides iterative execution. Ordinarily used to step through a container or to repeat a calculation a given number of times.

goto statement Statement that causes an unconditional transfer of control to a specified labeled statement elsewhere in the same function. gotos obfuscate the flow of control within a program and should be avoided.

if else statement Conditional execution of code following the if or the else, depending on the truth value of the condition.

if statement Conditional execution based on the value of the specified condition. If the condition is true, then the if body is executed. If not, control flows to the statement following the if.

labeled statement Statement preceded by a label. A label is an identifier followed by a colon. Label identifiers are independent of other uses of the same identifier.

null statement An empty statement. Indicated by a single semicolon.

raise Often used as a synonym for throw. C++ programmers speak of “throwing” or “raising” an exception interchangeably.

range for statement Statement that iterates through a sequence.

switch statement A conditional statement that starts by evaluating the expression that follows the switch keyword. Control passes to the labeled statement with a case label that matches the value of the expression. If there is no matching label, execution either continues at the default label, if there is one, or falls out of the switch if there is no default label.

terminate Library function that is called if an exception is not caught. terminate aborts the program.

throw expression Expression that interrupts the current execution path. Each throw throws an object and transfers control to the nearest enclosing catch clause that can handle the type of exception that is thrown.

try block Block enclosed by the keyword try and one or more catch clauses. If the code inside a try block raises an exception and one of the catch clauses matches the type of the exception, then the exception is handled by that catch. Otherwise, the exception is handled by an enclosing try block or the program terminates.

while statement Iteration statement that executes its target statement as long as a specified condition is true. The statement is executed zero or more times, depending on the truth value of the condition.