std::basic_string::append

basic_string& append( size_type count, CharT ch );	(1)
basic_string& append( const basic_string& str );	(2)
	(3)
basic_string& append( const basic_string& str, size_type pos, size_type count );	(until C++14)
basic_string& append( const basic_string& str, size_type pos, size_type count = npos );	(since C++14)
basic_string& append( const CharT* s, size_type count );	(4)
basic_string& append( const CharT* s );	(5)
template< class InputIt > basic_string& append( InputIt first, InputIt last );	(6)
basic_string& append( std::initializer_list<CharT> ilist );	(7)	(since C++11)
basic_string& append( std::basic_string_view<CharT, Traits> sv );	(8)	(since C++17)
template < class T > basic_string& append( const T& t, size_type pos, size_type count = npos );	(9)	(since C++17)

在字符串中追加其他字符。

1%29附件count字符副本ch

2%29附加字符串str

3%29追加一个子字符串[pos, pos+count)成str如果请求的子字符串持续到字符串的末尾，或者count == npos，附加的子字符串是[pos, size()).如果pos >= str.size()，，，std::out_of_range被扔了。

4%29附录一count所指向的字符串字符s...s可以包含空字符。

5%29附加以空结尾的字符串。s字符串的长度由第一个空字符决定。

6%29个附加字符在范围内[first, last)。此重载与重载%281%29的效果相同，如果InputIt是一个整体类型。

7%29追加初始化程序列表中的字符ilist...

8%29追加字符串视图中的所有字符sv好像append(sv.data(), sv.size())

9%29名皈依者t到字符串视图sv好像std::basic_string_view<charT, traits> sv = t;，然后从子视图中追加字符。[pos, pos+count)成sv.如果所请求的子视图扩展到sv，或者如果count == npos，附加的子视图是[pos, sv.size()).如果pos >= sv.size()，，，std::out_of_range被扔了。此重载只参与在下列情况下的重载解决方案：std::is_convertible_v<const T&,std::basic_string_view<CharT, Traits>>是true和std::is_convertible_v<const T&, const CharT*>是false...

参数

count	-	number of characters to append
pos	-	the index of the first character to append
ch	-	character value to append
first, last	-	range of characters to append
str	-	string to append
s	-	pointer to the character string to append
ilist	-	initializer list with the characters to append
sv	-	std::basic_string_view with the characters to append
t	-	object convertible to std::basic_string_view with the characters to append

返回值

*this...

复杂性

没有标准的复杂性保证，典型的实现行为类似于STD：：向量：：插入...

例外

如果出于任何原因引发异常，则此函数没有效果%28强异常保证%29。%28自C++11%29。

如果手术会导致size() > max_size()，抛std::length_error...

例

二次

#include <string>
#include <iostream>
 
int main() {
    std::basic_string<char> str = "string";
    const char* cptr = "C-string";
    const char carr[] = "Two and one";
 
    std::string output;
 
    // 1) Append a char 3 times. 
    // Notice, this is the only overload accepting chars.
    output.append(3, '*');
    std::cout << "1) " << output << "\n";
 
    //  2) Append a whole string
    output.append(str);
    std::cout << "2) " << output << "\n";
 
    // 3) Append part of a string (last 3 letters, in this case)
    output.append(str, 3, 3);
    std::cout << "3) " << output << "\n";
 
    // 4) Append part of a C-string
    // Notice, because `append` returns *this, we can chain calls together
    output.append(1, ' ').append(carr, 4);
    std::cout << "4) " << output << "\n";
 
    // 5) Append a whole C-string
    output.append(cptr);
    std::cout << "5) " << output << "\n";
 
    // 6) Append range
    output.append(&carr[3], std::end(carr));
    std::cout << "6) " << output << "\n";
 
    // 7) Append initializer list
    output.append({ ' ', 'l', 'i', 's', 't' });
    std::cout << "7) " << output << "\n";
}

二次

产出：

二次

1) ***
2) ***string
3) ***stringing
4) ***stringing Two 
5) ***stringing Two C-string
6) ***stringing Two C-string and one
7) ***stringing Two C-string and one list

二次

另见

operator+=	appends characters to the end (public member function)
strcat	concatenates two strings (function)
strncat	concatenates a certain amount of characters of two strings (function)
wcscat	appends a copy of one wide string to another (function)
wcsncat	appends a certain amount of wide characters from one wide string to another (function)

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最后更新于：2017-12-18