c ++查找向量函数<unsigned char>

Question

我想在vector<unsigned char> message找到空的空格char " "

vector<unsigned char>::iterator pos;
pos = find(message.begin(), message.end(), " ");

我收到一个错误：

/usr/include/c++/4.5/bits/stl_algo.h: In function ‘_RandomAccessIterator std::__find(_RandomAccessIterator, _RandomAccessIterator, const _Tp&, std::random_access_iterator_tag) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<unsigned char*, std::vector<unsigned char> >, _Tp = char [2]]’:
/usr/include/c++/4.5/bits/stl_algo.h:4209:45:   instantiated from ‘_IIter std::find(_IIter, _IIter, const _Tp&) [with _IIter = __gnu_cxx::__normal_iterator<unsigned char*, std::vector<unsigned char> >, _Tp = char [2]]’
../source/InveritasServer.cpp:107:49:   instantiated from here
/usr/include/c++/4.5/bits/stl_algo.h:158:4: error: ISO C++ forbids comparison between pointer and integer
/usr/include/c++/4.5/bits/stl_algo.h:4209:45:   instantiated from ‘_IIter std::find(_IIter, _IIter, const _Tp&) [with _IIter = __gnu_cxx::__normal_iterator<unsigned char*, std::vector<unsigned char> >, _Tp = char [2]]’
../source/InveritasServer.cpp:107:49:   instantiated from here
/usr/include/c++/4.5/bits/stl_algo.h:162:4: error: ISO C++ forbids comparison between pointer and integer
/usr/include/c++/4.5/bits/stl_algo.h:166:4: error: ISO C++ forbids comparison between pointer and integer
/usr/include/c++/4.5/bits/stl_algo.h:170:4: error: ISO C++ forbids comparison between pointer and integer
/usr/include/c++/4.5/bits/stl_algo.h:178:4: error: ISO C++ forbids comparison between pointer and integer
/usr/include/c++/4.5/bits/stl_algo.h:182:4: error: ISO C++ forbids comparison between pointer and integer
/usr/include/c++/4.5/bits/stl_algo.h:186:4: error: ISO C++ forbids comparison between pointer and integer

Answer 1

您应该使用' '而不是" " ：

pos = find(message.begin(), message.end(), ' ');

请注意， " "是字符串文字，而' '是字符文字。 你需要提供的第三个参数是字符文字，因为message是字符的向量，而不是字符串。

Answer 2

您正在搜索字符串，而不是unsigned char 。

尝试这个。 注意单引号。

pos = find(message.begin(), message.end(), ' ');

Answer 3

它是“unsigned char”的向量，你试图在其中找到一个字符串。 发送unsigned char类型。