string.begin()在studio和C++中的区别

string.begin()在C++中可以获取指针然后作为char*来处理，而在studio中却不可以，这个要怎么处理？

1.//c++时间函数及转换 #include <time.h>#include <stdio.h>int main(int argc, char * argv[]) 2. 两个文件：1〉TextQueryMain.cpp#include <iostream>#include "TextQuery.h"#include <fstream>using namespace std;ifstream& open_file(ifstream&, const string&);void print_results(const set<TextQuery::line_no>&, const string&, const TextQuery&);string make_plural(size_t, const string&, const string&);int main() TextQuery tq; tq.read_file(infile); while(true)   set<TextQuery::line_no> locs = tq.run_query(s);  print_results(locs, s, tq); } system("pause"); return 0;}void print_results(const set<TextQuery::line_no>& locs, const string& sought, const TextQuery& file)}ifstream& open_file(ifstream& in, const string& path)string make_plural(size_t size, const string& str, const string& strs)  2〉TextQuery.h#ifndef TEXTQUERY_H#define TEXTQUERY_H#include <iostream>#include <fstream>#include <vector>#include <string>#include <set>#include <map>#include <sstream>#include <string>using namespace std;class TextQuery //const? std::set<line_no> run_query(const std::string&) const; std::string text_line(line_no) const;private: void store_file(std::ifstream&); void build_map(); std::vector<std::string> line_of_text; std::map< std::string, std::set<line_no> > word_map;};// input file to vectorvoid TextQuery::store_file(std::ifstream& is)}//map initvoid TextQuery::build_map() }}set<TextQuery::line_no> TextQuery::run_query(const std::string& query_word) conststring TextQuery::text_line(TextQuery::line_no line) const#endif