std::basic_string<CharT,Traits,Allocator>::swap

 

C++

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符号索引

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字符串库

类

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string

成员函数 basic_string::basic_string basic_string::~basic_string basic_string::operator= basic_string::assign basic_string::assign_range (C++23)   basic_string::get_allocator 元素访问 basic_string::at basic_string::operator[] basic_string::front (DR*) basic_string::back (DR*) basic_string::data basic_string::c_str basic_string::operator  basic_string_view (C++17) 迭代器 basic_string::beginbasic_string::cbegin (C++11) basic_string::endbasic_string::cend (C++11) basic_string::rbeginbasic_string::crbegin (C++11) basic_string::rendbasic_string::crend (C++11) 搜索 basic_string::find basic_string::rfind basic_string::find_first_of basic_string::find_first_not_of basic_string::find_last_of basic_string::find_last_not_of

修改器 basic_string::clear basic_string::insert basic_string::insert_range (C++23) basic_string::erase basic_string::push_back basic_string::pop_back (DR*) basic_string::append basic_string::append_range (C++23) basic_string::operator+= basic_string::replace basic_string::replace_with_range (C++23) basic_string::copy basic_string::resize basic_string::resize_and_overwrite (C++23)  basic_string::swap 容量 basic_string::empty basic_string::sizebasic_string::length basic_string::max_size basic_string::reserve basic_string::capacity basic_string::shrink_to_fit (DR*) 操作 basic_string::compare basic_string::starts_with (C++20) basic_string::ends_with (C++20) basic_string::contains (C++23) basic_string::substr

常量 basic_string::npos 非成员函数 operator+ swap(std::basic_string) erase(std::basic_string)erase_if(std::basic_string) (C++20)(C++20) I/O operator<<operator>> getline 比较 operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) 数值转换 stoistolstoll (C++11)(C++11)(C++11) stoulstoull (C++11)(C++11)  stofstodstold (C++11)(C++11)(C++11) to_string (C++11) to_wstring (C++11) 字面量 operator""s (C++14) 辅助类 hash<std::basic_string> (C++11) Deduction guides (C++17)

 

void swap( basic_string& other );		(until C++17)
void swap( basic_string& other ) noexcept(/* see below */);		(since C++17) (constexpr since C++20)

与 other 交换字符串的内容。所有迭代器和引用都可能失效。

如果 std::allocator_traits<Allocator>::     propagate_on_container_swap::value && get_allocator() == s.get_allocator() 为 false，则行为未定义。

(since C++11)

参数

other

-

与其交换内容的字符串

复杂度

常量。

异常

不抛出异常。	(until C++11)
不抛出异常，除非行为未定义。 如果由于任何原因抛出异常，则此函数无效（强异常安全保证）。	(since C++11)

noexcept 规范：   noexcept(std::allocator_traits<Allocator>::propagate_on_container_swap::value ||          std::allocator_traits<Allocator>::is_always_equal::value)

(since C++17)

示例

运行此代码

#include <iostream>
#include <string>
 
int main() 
{
    std::string a = "AAA";
    std::string b = "BBBB";
 
    std::cout << "Before swap:\n"
                 "a = " << a << "\n"
                 "b = " << b << "\n\n";
 
    a.swap(b);
 
    std::cout << "After swap:\n"
                 "a = " << a << "\n"
                 "b = " << b << '\n';
}

输出

Before swap:
a = AAA
b = BBBB
 
After swap:
a = BBBB
b = AAA

缺陷报告

以下行为变更缺陷报告被追溯应用于先前发布的 C++ 标准。

DR	应用于	已发布行为	正确行为
LWG 403	C++98	swap() 可能抛出异常	不抛出异常
LWG 535	C++98	交换字符串不会保留字符顺序	顺序也被保留
LWG 2151 (P1148R0)	C++11	在以下情况下未抛出异常 不相等非传播分配器	此情况下的行为是 未定义的

参见

swap	交换两个对象的值 (函数模板)
swap_ranges	交换两个元素范围 (函数模板)
swap	swaps the contents (public member function of std::basic_string_view<CharT,Traits>)