關於C++標准異常之std::out_of_range

簡介

定義於頭文件 <stdexcept>
class out_of_range;

定義要作為異常引發的對象類型。它報告試圖訪問定義范圍之外的元素所導致的錯誤。它可以由std：：bitset和std：：basic_string的成員函數、std：：stoi和std：：stod函數族以及邊界檢查的成員訪問函數（例如std：：vector：：at和std：：map：：at）拋出。
繼承關系如下：

 

成員函數

Member functions

(constructor)	constructs a new out_of_range object with the given message (public member function)
operator=	replaces the out_of_range object (public member function)
what	returns the explanatory string (public member function)

std::out_of_range::out_of_range

out_of_range( const std::string& what_arg );	(1)
out_of_range( const char* what_arg );	(2)	(since C++11)
	(3)
out_of_range( const out_of_range& other );		(until C++11)
out_of_range( const out_of_range& other ) noexcept;		(since C++11)

1-2) Constructs the exception object with what_arg as explanatory string that can be accessed through what().

3) Copy constructor. If *this and other both have dynamic type std::out_of_range then std::strcmp(what(), other.what()) == 0. (since C++11)

Parameters

what_arg	-	explanatory string
other	-	another exception object to copy

Exceptions

1-2) May throw std::bad_alloc

Notes

Because copying std::out_of_range is not permitted to throw exceptions, this message is typically stored internally as a separately-allocated reference-counted string. This is also why there is no constructor taking std::string&&: it would have to copy the content anyway.

std::out_of_range::operator=

out_of_range& operator=( const out_of_range& other );		(until C++11)
out_of_range& operator=( const out_of_range& other ) noexcept;		(since C++11)

Assigns the contents of other. If *this and other both have dynamic type std::out_of_range then std::strcmp(what(), other.what()) == 0 after assignment. (since C++11)

Parameters

other

-

another exception object to assign

Return value

*this

std::out_of_range::what

virtual const char* what() const throw();		(until C++11)
virtual const char* what() const noexcept;		(since C++11)

Returns the explanatory string.

Parameters

(none)

Return value

Pointer to a null-terminated string with explanatory information.

Notes

Implementations are allowed but not required to override what().