尝试转换 str 字符串以在 std::getline 分隔符中使用
我试图获取 std::string 值并将其用作 std::getline() 函数中的分隔符 但无论我做什么,编译器都会给我错误。 这就是我想要做的:
std::stringstream ss(s);
std::string item;
std::string delim ="&&=";
int ssize = delim.size();
int newssize = ssize+1;
char del[SSIZE]; // also here when i try gives error
strcpy(del,delim.c_str());
char * delrr[1024] = delim.c_str(); //gives error
while(std::getline(ss,item,delrr)) {
elems.push_back(item);
}
我得到的错误始终与 const char* 转换有关。
error C2440: 'initializing' : cannot convert from 'const char *' to 'char *[1024]'
1> There are no conversions to array types, although there are conversions to references or pointers to arrays
1>.\UT.cpp(179) : error C2780: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &)' : expects 2 arguments - 3 provided
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(527) : see declaration of 'std::getline'
1>.\UT.cpp(179) : error C2784: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem)' : could not deduce template argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::stringstream'
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(475) : see declaration of 'std::getline'
1>.\UT.cpp(179) : error C2784: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem)' : could not deduce template argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::stringstream'
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(475) : see declaration of 'std::getline'
1>.\UT.cpp(179) : error C2782: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem)' : template parameter '_Elem' is ambiguous
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(475) : see declaration of 'std::getline'
1> could be 'char **'
1> or 'char'
更新:
找到了答案: 如何在 C++ 中标记字符串?
http://www.codeproject.com/Articles/23198/ C-String-Toolkit-StrTk-Tokenizer
im trying to take std::string
value and use it as delimiter in std::getline()
function
but no mater what i do the compiler gives me error.
this is what im trying to do :
std::stringstream ss(s);
std::string item;
std::string delim ="&&=";
int ssize = delim.size();
int newssize = ssize+1;
char del[SSIZE]; // also here when i try gives error
strcpy(del,delim.c_str());
char * delrr[1024] = delim.c_str(); //gives error
while(std::getline(ss,item,delrr)) {
elems.push_back(item);
}
the error im getting is always about const char* convertion .
error C2440: 'initializing' : cannot convert from 'const char *' to 'char *[1024]'
1> There are no conversions to array types, although there are conversions to references or pointers to arrays
1>.\UT.cpp(179) : error C2780: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &)' : expects 2 arguments - 3 provided
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(527) : see declaration of 'std::getline'
1>.\UT.cpp(179) : error C2784: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem)' : could not deduce template argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::stringstream'
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(475) : see declaration of 'std::getline'
1>.\UT.cpp(179) : error C2784: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem)' : could not deduce template argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::stringstream'
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(475) : see declaration of 'std::getline'
1>.\UT.cpp(179) : error C2782: 'std::basic_istream<_Elem,_Traits> &std::getline(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &,const _Elem)' : template parameter '_Elem' is ambiguous
1> d:\Program Files\Microsoft Visual Studio 9.0\VC\include\string(475) : see declaration of 'std::getline'
1> could be 'char **'
1> or 'char'
UPDATE:
found the answer:
How do I tokenize a string in C++?
http://www.codeproject.com/Articles/23198/C-String-Toolkit-StrTk-Tokenizer
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getline() 的第三个参数是字符,而不是字符数组。请参阅此。如果需要多个分隔符或由多个字符组成的分隔符,则不能使用此功能。
使用 find() 和 substr()。
The third argument of getline() is a char, not a char array. See this. You cannot use this function if you need multiple delimiters or a delimiter made of multiple characters.
Use find() and substr().
std::string::c_str() 为您提供一个指向字符数组的指针。为了使用
c_str()
调用的结果填充字符数组,您需要使用strcpy()
或strncpy()
> 因为它们实际上复制了 C 样式字符串。另外,您已将
delrr
声明为 1024 个字符指针的数组,而不是 1024 个字符,这真的是意图吗?std::string::c_str() gives you a pointer to a character array. In order to fill a character array with the results of the call to
c_str()
you'll need to usestrcpy()
orstrncpy()
as those actually copy the C style string.Also, you've declared
delrr
as an array of 1024 character pointers rather than 1024 characters, is that really the intent?