string find

#include <iostream>#include <vector>#include <string>#include <tchar.h>#include <string.h>using namespace std;/************************************************************************//*  查找一个字符在一个字符串中第n次出现的位置    first parameter str: source string    second parameter c: find char    third parameter n: Nst show    return : index of c in str*//************************************************************************/int FindNstPosition(const char* str, char c, int n){    // ASSERT(str);    if(!str || c == '\0')        return -1;    const char * p = str;    int nIndex = 0;    int nCount = 0;    while(*p != '\0')    {        if(*p == c)        {            nCount++;            if(nCount == n)                return nIndex;            else            {                nIndex++;                p++;            }        }        else        {            nIndex++;            p++;        }    }    return -1;}/************************************************************************//*  以指定的分割符分割字符串，并将分割后的字符串放到vector<string>中    src: source string    separator : separator string    dest : dest vector string*//************************************************************************/void mySplit(const string& src, const string& separator, vector<string>& dest){    string str = src;    string substring = "";    string::size_type start = 0, nIndex = 0;    do     {        nIndex = str.find_first_of(separator, start);        if(nIndex != string::npos)        {            substring = str.substr(start, nIndex - start);            dest.push_back(substring);            start = str.find_first_not_of(separator, nIndex);            if(start == string::npos)                return;        }    } while (nIndex != string::npos);    // the last token    substring = str.substr(start);    dest.push_back(substring);}int main(){    vector<string> vecStr;    vecStr.push_back("test1&test2&test3&test4&test5&test6");    cout << vecStr[0] << endl;    cout << "sizeof(vecStr[0]) = " << sizeof(vecStr[0]) << endl;    cout << "strlen(vecStr[0]) = " << strlen(vecStr[0].c_str()) << endl;    int nIndex = FindNstPosition(vecStr[0].c_str(), 'e', 5);    cout << nIndex << endl;    cout << endl;    vector<string> strDest;    string separator = "&";    mySplit(vecStr[0], separator, strDest);    for(size_t i = 0; i < strDest.size(); i++)        cout << strDest[i] << endl;    system("pause");    return 0;}