c++实现split

来自cplusplus.com

 // Class splitstring which adds method split()

// define MAIN if this is a standalone program
#define MAIN 1

#include <string>
#include <vector>
#include <iostream>
using namespace std;


class splitstring : public string {
vector<string> flds;
public:
splitstring(char *s) : string(s) { };
vector<string>& split(char delim, int rep=0);
};

// split: receives a char delimiter; returns a vector of strings
// By default ignores repeated delimiters, unless argument rep == 1.
vector<string>& splitstring::split(char delim, int rep) {
if (!flds.empty()) flds.clear(); // empty vector if necessary
string work = data();
string buf = "";
int i = 0;
while (i < work.length()) {
if (work[i] != delim)
buf += work[i];
else if (rep == 1) {
flds.push_back(buf);
buf = "";
} else if (buf.length() > 0) {
flds.push_back(buf);
buf = "";
}
i++;
}
if (!buf.empty())
flds.push_back(buf);
return flds;
}

#ifdef MAIN
main()
{
// we define a string
splitstring s("Humpty Dumpty sat on a wall. Humpty Dumpty had a great fall");
cout << s << endl;

// splits and displays the vector of strings
vector<string> flds = s.split(' ');
for (int k = 0; k < flds.size(); k++)
cout << k << " => " << flds[k] << endl;

// now taking account of repeated delimiters
cout << endl << "with repeated delimiters:" << endl;
vector<string> flds2 = s.split(' ', 1);
for (int k = 0; k < flds2.size(); k++)
cout << k << " => " << flds2[k] << endl;

}
#endif