The fifth Chapter C + +: Statements related to the introduction

Fifth Chapter Statement

Pendant else

The question of how to find a matching if branch for else when the if branch is hiding from the Else branch:
-C + + stipulates that else matches the not-so-recent if match, which eliminates the two semantics.

Switch

Switch (CH) {case    ' a ': Case    ' B ':        ++n;        break;}

• Break jumps out of the switch control flow.

• The case label (case lable) must be an integer constant expression .

• If a case label succeeds, all branches will be executed sequentially from the label, unless the interrupt is shown, until the end of switch is stopped.

• The statement after the case label, with curly braces ({}), defines the variable within the block, ensuring that all subsequent case labels are outside the scope of the variable.

• Default tag: A special case label that executes the contents of the default tag when switch does not match all cases.

Do While

Do    statementwhile (condition);  Note Semicolon

• Defining variables within a loop condition is not allowed.

• And the variables of the conditional part must be defined outside the loop body.

Jump statement

• Break

  is responsible for terminating the while, do, and for or switch statements that are closest to it, and starting with the first statement after the statements.

• Continue

  For, while, do and

Try statement block and exception handling

• throw-expression (Throw expression): The Exception detection section uses a throw expression to indicate that it has encountered an issue that cannot be handled.
  

• Called throw** (Raise) an exception.

• After an exception is thrown, the function is terminated and control is transferred to the code that can handle the exception.

• try Block (try block): Try to start with one or more catch clauses (catch clause) end.
  

• Exceptions that are thrown by code in a try statement block are usually handled by a catch clause.

• The catch clause is called the Exception handling code (exception handler).

• Exception classes (Exception Class)

try {    //program-statements} catch (/*exception-declaration exception declaration */) {    //handler-statements} catch (/* exception-declaration*/) {    //handler-statements}//...

• An exception declaration specifies the type of exception that the catch clause can handle.

Standard exceptions

The C + + standard library defines a set of classes that report problems encountered by standard library functions.
In the following 4 header files:
-Exception: Defines the most common exception class exception, which only reports the occurrence of exceptions and does not provide any additional information.
-Stdexcept
-Class with a string object or a C-style literal.
-Only one member function what ()

exception //最常见的问题
runtime_error //只有在运行时才能检测出的问题
overflow_error //
underflow_error
logic_error
domain_error
invalid_arguement
length_error
out_og_range

-New:bad_alloc
-Type_info:bad_cast

Reference: C++primer Fifth Edition

Related articles:

Fourth C + +: Application of expression concept-operator

sixth C + +: Function basics and application