错误:ISO C++禁止指针和整数之间的比较

Question

这里有一些代码我想在字符串中找到所需的子字符串块:

#include <algorithm>
#include <string> 
using namespace std;

...
unsigned int stage = 3;
string::iterator iter = s.begin();
string::iterator iter_next = s.end();

for (unsigned int i=0; i<stage; i++) {

    iter = std::find(iter, s.end(),"#STAGE");

}
    iter_next = std::find(iter, s.end(), "#STAGE");

string sub = string(iter, iter_next);
...

我选择返回迭代器而不是索引.但是,调试给我这个:

error: ISO C++ forbids comparison between pointer and integer. 

c:\qtsdk\mingw\bin\..\lib\gcc\mingw32\4.4.0\include\c++\bits\stl_algo.h:-1: 
In function '_RandomAccessIterator std::__find(_RandomAccessIterator, _RandomAccessIterator, 
const _Tp&, std::random_access_iterator_tag) [with _RandomAccessIterator =   
__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, 
std::allocator<char> > >, _Tp = char [7]]':
c:\qtsdk\mingw\bin\..\lib\gcc\mingw32\4.4.0\include\c++\bits\stl_algo.h:4224: instantiated  
from '_IIter std::find(_IIter, _IIter, const _Tp&) [with _IIter = 
__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, 
std::allocator<char> > >, _Tp = char [7]]'

当我使用索引方法时,一切都很好.我明白这一定是一个简单的错误,但我希望有人可以指出.

Answer 1

iter = std::find(iter, s.end(),"#STAGE");

这是不对的.你不能找到string在string使用std::find.只有性格.

你可以简单地使用

size_t pos = s.find("#STAGE");

并创建迭代器

iter = s.begin() + pos;

如果pos不等于std::string::npos.