< C++ > string c_str

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本文介绍如何使用c_str()方法将C++中的std::string对象转换为C风格的字符串（const char*）。通过示例展示了如何将string类型的变量传递给需要char*参数的函数。
c_str() 以const char* 类型返回 string 内含的字符串
如果一个函数要求char*参数，可以使用c_str()方法：
string s = "Hello World!";
printf("%s", s.c_str()); //输出 "Hello World!"
C++中为string为何叫basic_string＜char＞
Pass-by
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//假设下面是basic_string类的定义（不用关系它定义是否完整），那么就有一个疑问？ //难道字符串的还有不同的类型吗？需要使用模版 template <class T> class basic_string { private: T* _str; //... }; 这里就需要了解一下编码： 编码的由来： 计算机只能计算和识别二进制，必须让计算机识别文字，才能和计算机进行交互，彼此也才能通过计算机通信。 由此，有了ASCII编码的诞生，它起始于50年代后期，在1967年定案，是.
【C++初阶篇】C++中c_str函数的全面解析
braveact的博客
04-05 1703
c_str()函数是std::string类的一个成员函数，其原型为：该函数返回一个指向std::string对象内部字符数组的常量指针，该数组以空字符结尾。noexcept关键字表示该函数不会抛出异常，确保了其安全性。本篇文章深入剖析了C++中c_str()函数。它详细介绍了c_str()函数的定义、返回值特性，如只读性、生命周期及空字符结尾。文章还探讨了c_str()函数的使用场景，包括与C标准库函数交互、文件操作及系统调用。
C++中的 c_str() 函数
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YXXXYX的博客
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功能：c_str() 函数可以将 const string* 类型 转化为 cons char* 类型 头文件：#include<cstring> c_str()就是将C++的string转化为C的字符串数组，c_str()生成一个const char *指针，指向字符串的首地址 因为在c语言中没有string类型，必须通过string类对象的成员函数 c_str() 把 string 转换成c中的字符串样式 注意点： c_str() 这个函数转换后返回的是一个临时指针，不能对其进行操作
C++ vector＜string＞转string
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采用accumulate函数 #include <vector> #include <string> #include <numeric> // 函数所在的库 #include <iostream> using namespace std; int main() { string strData; vector<string> vec = { "hello world" }; strData = accumulate(vec.beg
C++ string类 c_str()的用法详解
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//标准库的string类提供了三个成员函数来从一个string得到c类型的字符数组 //主要介绍c_str //c_str()：生成一个const char*指针，指向以空字符终止的数组。 //这个数组应该是string类内部的数组 #include <iostream> //需要包含cstring的字符串 #include <cstring> using namespa...
C++ vector＜int＞ 转 string
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直接上干货 #include <vector> #include <iostream> #include <sstream> #include <iterator> #include <string> using namespace std; int main() { vector<int> vec = {1,2,3,4}; stringstream ss; string str; copy(vec.begin(), ve
c++ string c_str() 和data()区别
weixin_42229663的博客
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const char * c_str（）const; 获取等效的C字符串 生成一个以空终止的字符序列（c-string），其内容与字符串对象相同，并将其作为指向字符数组的指针返回。 会自动附加一个终止的空字符。 const char * data（）const; 获取字符串数据 返回指向与字符串内容相同的字符数组的指针。 请注意，没有附加任何终止的空字符（有关此功能，请参阅成员c_str）。 c_str()字符串后有'\0'，而data()没有。 ......
#include＜string＞ #include＜cstring＞
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C++ strings //string input //string 类型可以直接比较string comparisons string str,str2; if(str>str2) if(str==str2) if(str<str2) //下图本是定义的时候，习惯写成了赋值initiallisation //字符串的赋值assingment //交换Swapping strings //string concatention...
C++ ＜string＞ 标头文件详解
weixin_74396256的博客
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是 C++ 标准库中的头文件之一，定义了 std::string 类。std::string 是一个动态大小的字符序列，可以像数组一样通过下标访问字符，同时支持自动内存管理。在 C++ 中，std::string 替代了 C 风格的字符串（字符数组），让我们能够更方便、灵活地处理文本数据。std::string 是一个功能丰富、强大的类，极大简化了 C++ 中的字符串处理。通过std::string，我们可以轻松完成字符串的创建、修改、查找、转换等操作，而不用担心手动管理内存。
C++ string、vector＜char＞和(const)char *之间的转换
weixin_38331755的博客
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写C++程序时经常会遇到string、vector<char>和(const)char *之间的转换，本文介绍了其间的转换方法和注意事项。 1. string转vector<char> string所存储字符串不包含'\0'，所以转为vector后，通过vector.data()直接输出会有问题,会往后找直到'\0'，会出现乱码。所以应该在vector后手动再加上'\0'，这样在vector.data()输出字符串就没问题了。但此时vector.size()会比string.le
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C++ 运行时绑定
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C++ 动态绑定 C++ 的虚函数 + 派生类对象及派生类到基类的类型转换 共同完成了C++ 面向对象程序设计的三个基本概念之一--动态绑定。 同样一段代码运行时才能决定运行的具体函数是哪个（相对于编译时就能确定而言），这个概念在C++ 中称为动态绑定或运行时绑定（run-time binding）。 例如，定义下面一个接口用于打印书籍的总价格，这个接口既可以用于打印没有折扣的书籍价格（基类
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摘自 C++ primer 5th edition: Let’s look at another topic from C++’s bag of new tricks: the default argument. A default argu- ment is a value that’s used automatically if you omit the corresponding act
C++ 纯虚函数
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纯虚函数： 和普通的虚函数不一样，纯虚函数无需定义。通过在函数体的位置书写 =0 就可以将一个虚函数声明为纯虚函数。 含有纯虚函数的类是抽象类（abstract base class）。抽象类负责定义接口，后续的其他类可以覆盖该接口。C++ 不允许创建一个抽象类的对象。 看个例子： //==================================================
C/C++ 二维数组、多维数组
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int or unsigned int
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C++ 构造函数 C++ 中定义全局的对象，会引发该对象对应类及其父类的构造函数执行，因此可先于main() 函数执行。 如： #include using namespace std; // Base class defination class Quote { public: Quote() = default; Quote(const std::string &bo
c++ vector
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https://en.cppreference.com/w/cpp/container/vector #include <iostream> #include <vector> int main() { // Create a vector containing integers std::vector<int> v = {7, 5, 16, 8}; // Add two more integers to vector v.
In file included from /usr/include/x86_64-linux-gnu/c++/8/bits/c++allocator.h:33, from /usr/include/c++/8/bits/allocator.h:46, from /usr/include/c++/8/string:41, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/ext/new_allocator.h: In instantiation of 'void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = std::__cxx11::basic_string<char>; _Args = {const char&}; _Tp = std::_Rb_tree_node<std::__cxx11::basic_string<char> >]': /usr/include/c++/8/bits/alloc_traits.h:475:4: required from 'static void std::allocator_traits<std::allocator<_CharT> >::construct(std::allocator_traits<std::allocator<_CharT> >::allocator_type&, _Up*, _Args&& ...) [with _Up = std::__cxx11::basic_string<char>; _Args = {const char&}; _Tp = std::_Rb_tree_node<std::__cxx11::basic_string<char> >; std::allocator_traits<std::allocator<_CharT> >::allocator_type = std::allocator<std::_Rb_tree_node<std::__cxx11::basic_string<char> > >]' /usr/include/c++/8/bits/stl_tree.h:626:32: required from 'void std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_construct_node(std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Link_type, _Args&& ...) [with _Args = {const char&}; _Key = std::__cxx11::basic_string<char>; _Val = std::__cxx11::basic_string<char>; _KeyOfValue = std::_Identity<std::__cxx11::basic_string<char> >; _Compare = Compare; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Link_type = std::_Rb_tree_node<std::__cxx11::basic_string<char> >*]' /usr/include/c++/8/bits/stl_tree.h:643:4: required from 'std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(_Args&& ...) [with _Args = {const char&}; _Key = std::__cxx11::basic_string<char>; _Val = std::__cxx11::basic_string<char>; _KeyOfValue = std::_Identity<std::__cxx11::basic_string<char> >; _Compare = Compare; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_Link_type = std::_Rb_tree_node<std::__cxx11::basic_string<char> >*]' /usr/include/c++/8/bits/stl_tree.h:2400:13: required from 'std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_emplace_equal(_Args&& ...) [with _Args = {const char&}; _Key = std::__cxx11::basic_string<char>; _Val = std::__cxx11::basic_string<char>; _KeyOfValue = std::_Identity<std::__cxx11::basic_string<char> >; _Compare = Compare; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator = std::_Rb_tree_iterator<std::__cxx11::basic_string<char> >]' /usr/include/c++/8/bits/stl_multiset.h:458:63: required from 'std::multiset<_Key, _Compare, _Alloc>::iterator std::multiset<_Key, _Compare, _Alloc>::emplace(_Args&& ...) [with _Args = {const char&}; _Key = std::__cxx11::basic_string<char>; _Compare = Compare; _Alloc = std::allocator<std::__cxx11::basic_string<char> >; std::multiset<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree_const_iterator<std::__cxx11::basic_string<char> >]' solution.cpp:34:43: required from here /usr/include/c++/8/ext/new_allocator.h:136:4: error: no matching function for call to 'std::__cxx11::basic_string<char>::basic_string(const char&)' { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/c++/8/string:52, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/bits/basic_string.h:649:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::__sv_wrapper, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(__sv_wrapper __svw, const _Alloc& __a) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:649:7: note: candidate expects 2 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:639:2: note: candidate: 'template<class _Tp, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Tp&, const _Alloc&)' basic_string(const _Tp& __t, const _Alloc& __a = _Alloc()) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:639:2: note: template argument deduction/substitution failed: /usr/include/c++/8/bits/basic_string.h:628:2: note: candidate: 'template<class _Tp, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Tp&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&)' basic_string(const _Tp& __t, size_type __pos, size_type __n, ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:628:2: note: template argument deduction/substitution failed: In file included from /usr/include/x86_64-linux-gnu/c++/8/bits/c++allocator.h:33, from /usr/include/c++/8/bits/allocator.h:46, from /usr/include/c++/8/string:41, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/ext/new_allocator.h:136:4: note: candidate expects 4 arguments, 1 provided { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/c++/8/string:52, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/bits/basic_string.h:614:9: note: candidate: 'template<class _InputIterator, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(_InputIterator, _InputIterator, const _Alloc&)' basic_string(_InputIterator __beg, _InputIterator __end, ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:614:9: note: template argument deduction/substitution failed: In file included from /usr/include/x86_64-linux-gnu/c++/8/bits/c++allocator.h:33, from /usr/include/c++/8/bits/allocator.h:46, from /usr/include/c++/8/string:41, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/ext/new_allocator.h:136:4: note: candidate expects 3 arguments, 1 provided { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/c++/8/string:52, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/bits/basic_string.h:576:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(basic_string&& __str, const _Alloc& __a) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:576:7: note: candidate expects 2 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:572:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(const basic_string& __str, const _Alloc& __a) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:572:7: note: candidate expects 2 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:568:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::initializer_list<_Tp>, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc()) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:568:7: note: no known conversion for argument 1 from 'const char' to 'std::initializer_list<char>' /usr/include/c++/8/bits/basic_string.h:541:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(basic_string&& __str) noexcept ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:541:7: note: no known conversion for argument 1 from 'const char' to 'std::__cxx11::basic_string<char>&&' /usr/include/c++/8/bits/basic_string.h:529:7: note: candidate: 'template<class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, _CharT, const _Alloc&)' basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc()) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:529:7: note: template argument deduction/substitution failed: In file included from /usr/include/x86_64-linux-gnu/c++/8/bits/c++allocator.h:33, from /usr/include/c++/8/bits/allocator.h:46, from /usr/include/c++/8/string:41, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/ext/new_allocator.h:136:4: note: candidate expects 3 arguments, 1 provided { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/c++/8/string:52, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/bits/basic_string.h:514:7: note: candidate: 'template<class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&)' basic_string(const _CharT* __s, const _Alloc& __a = _Alloc()) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:514:7: note: template argument deduction/substitution failed: In file included from /usr/include/x86_64-linux-gnu/c++/8/bits/c++allocator.h:33, from /usr/include/c++/8/bits/allocator.h:46, from /usr/include/c++/8/string:41, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/ext/new_allocator.h:136:4: note: cannot convert 'std::forward<const char&>((* & __args#0))' (type 'const char') to type 'const char*' { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/c++/8/string:52, from /usr/include/c++/8/bits/locale_classes.h:40, from /usr/include/c++/8/bits/ios_base.h:41, from /usr/include/c++/8/ios:42, from main.cpp:7: /usr/include/c++/8/bits/basic_string.h:499:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]' basic_string(const _CharT* __s, size_type __n, ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:499:7: note: candidate expects 3 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:481:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]' basic_string(const basic_string& __str, size_type __pos, ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:481:7: note: candidate expects 4 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:465:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]' basic_string(const basic_string& __str, size_type __pos, ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:465:7: note: candidate expects 3 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:450:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]' basic_string(const basic_string& __str, size_type __pos, ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:450:7: note: candidate expects 3 arguments, 1 provided /usr/include/c++/8/bits/basic_string.h:437:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(const basic_string& __str) ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:437:7: note: no known conversion for argument 1 from 'const char' to 'const std::__cxx11::basic_string<char>&' /usr/include/c++/8/bits/basic_string.h:429:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:429:7: note: no known conversion for argument 1 from 'const char' to 'const std::allocator<char>&' /usr/include/c++/8/bits/basic_string.h:420:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string() [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' basic_string() ^~~~~~~~~~~~ /usr/include/c++/8/bits/basic_string.h:420:7: note: candidate expects 0 arguments, 1 provided
最新发布
06-07
### C++ 编译错误 'vector未声明' 和 'basic_string构造函数不匹配' 的解决方案 #### 1. 解决 'vector未声明' 的问题 编译错误 `'vector was not declared in this scope'` 表明程序中缺少对 `<vector>` 头文件的包含。标准模板库中的 `std::vector` 类型需要显式包含 `<vector>` 头文件[^1]。此外，如果直接使用 `vector` 而非 `std::vector`，则需要确保引入了 `std` 命名空间或使用 `using std::vector;`。 以下是正确的代码示例： ```cpp #include <vector> // 包含 vector 头文件 #include <iostream> int main() { std::vector<int> vec; // 正确声明 vector vec.push_back(42); // 添加元素 std::cout << vec[0] << std::endl; // 输出第一个元素 return 0; } ``` #### 2. 解决 'basic_string构造函数不匹配' 的问题 编译错误 `'basic_string构造函数不匹配'` 通常发生在尝试以不兼容的方式初始化 `std::string` 对象时。例如，传递了一个与预期类型不符的参数给 `std::string` 构造函数。`std::string` 是 `std::basic_string<char>` 的 typedef，因此其构造函数必须遵循特定的签名[^2]。 以下是一个可能导致此错误的示例及其修复方法： **错误代码：** ```cpp #include <string> #include <iostream> int main() { const char* cstr = "hello"; std::string str(cstr, 50); // 错误：cstr 长度不足 50 std::cout << str << std::endl; return 0; } ``` **修复后的代码：** ```cpp #include <string> #include <iostream> int main() { const char* cstr = "hello"; std::string str(cstr, strlen(cstr)); // 修复：使用正确的长度 std::cout << str << std::endl; return 0; } ``` 在上述修复中，`strlen(cstr)` 确保传递给 `std::string` 构造函数的长度与实际字符串长度一致。 #### 3. 综合示例 以下是一个综合示例，展示了如何同时解决 `vector` 和 `basic_string` 的相关问题： ```cpp #include <vector> // 包含 vector 头文件 #include <string> // 包含 string 头文件 #include <iostream> #include <cstring> // 包含 strlen 函数 int main() { // 正确声明和初始化 vector std::vector<std::string> vec; // 正确初始化 string 对象 const char* cstr = "hello"; std::string str(cstr, strlen(cstr)); // 使用正确的长度 vec.push_back(str); // 将 string 添加到 vector 中 std::cout << vec[0] << std::endl; // 输出 vector 中的第一个元素 return 0; } ``` #### 4. 注意事项 - 如果使用 `std::basic_string_view`（C++17 引入），它提供了一种轻量级的方式来引用字符序列，但不拥有底层数据[^3]。这可以避免不必要的字符串复制。 - 在多线程环境中操作 `std::vector` 或 `std::string` 时，需注意同步问题，以避免数据竞争。 --- ###
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