在字符串向量上使用 push_back - C++

Using push_back on a vector of strings - C++

提问by Sriram

I am trying to use push_backon a vector of strings in C++. How can I push a single character on to the vector? Currently, I have tried the following, all without success:

我正在尝试push_back在 C++ 中使用字符串向量。如何将单个字符推送到向量上？目前，我尝试了以下方法，但都没有成功：

1. Initialized a string (tried to) with the character.

1. 用字符初始化一个字符串（试图）。

Code

代码

string str(main_string[0]);  
vector_string.push_back(str);

1. Tried to invoke strcpy and thus copy contents. Const-ness seems to get in the way.

2. 试图调用 strcpy 并因此复制内容。Const-ness 似乎有碍观瞻。

Code

代码

string str;  
strcpy(main_string[0], str.c_str());  
vector_string.push_back(str);  

Any more suggestions/ideas are most welcome.

任何更多的建议/想法都是最受欢迎的。

Edit: The error logs are as follows:

编辑：错误日志如下：

test_push.C: In function ‘void test_push(std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&, std::string)':
test_push.C:50: error: no matching function for call to ‘std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char&)'
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:220: note: candidates are: std::basic_string<_CharT, _Traits, _Alloc>::basic_string(typename _Alloc::rebind<_CharT>::other::size_type, _CharT, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:213: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>] <near match>
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:206: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, typename _Alloc::rebind<_CharT>::other::size_type, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:194: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::basic_string<_CharT, _Traits, _Alloc>&, typename _Alloc::rebind<_CharT>::other::size_type, typename _Alloc::rebind<_CharT>::other::size_type, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:184: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::basic_string<_CharT, _Traits, _Alloc>&, typename _Alloc::rebind<_CharT>::other::size_type, typename _Alloc::rebind<_CharT>::other::size_type) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:170: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:178: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.h:2147: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string() [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
test_push.C:61: error: conversion from ‘char' to non-scalar type ‘std::string' requested
test_push:90: error: no matching function for call to ‘std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char&)'
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:220: note: candidates are: std::basic_string<_CharT, _Traits, _Alloc>::basic_string(typename _Alloc::rebind<_CharT>::other::size_type, _CharT, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:213: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>] <near match>
/usr/lib/gcc/i586-redhat-linux/4.4.1/../../../../include/c++/4.4.1/bits/basic_string.tcc:206: note:                 std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, typename _Alloc::rebind<_CharT>::other::size_type, const _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]  

More info: In this function, either the entire string or just the first letter is pushed in to the vector based on its contents. So, in a way, I am looking for some function that converts a charinto a C++ style std::string(to make it acceptable to a vector).

更多信息：在此函数中，整个字符串或仅第一个字母会根据其内容推送到向量中。所以，在某种程度上，我正在寻找一些将 achar转换为 C++ 风格的函数std::string（使其可以被向量接受）。

Thanks,
Sriram

谢谢，
斯里拉姆

回答by ali_bahoo

You can also initialize with one character like this.

您也可以使用这样的一个字符进行初始化。

string str(1,main_string[0]);  
vector_string.push_back(str);  

回答by Marcelo Cantos

You can add the character directly via an appropriate string constructor:

您可以通过适当的字符串构造函数直接添加字符：

vector_string.push_back(string(1, main_string[0]));

EDIT:Removed alternate solution after realising it duplicates @Tim's.

编辑：在意识到它重复了@Tim's后删除了替代解决方案。

回答by Tim

no need for strcpy for a single character.

单个字符不需要 strcpy 。

string str ("x");
str[0] = main_string[0]; 
vector_string.push_back(str);