在c++/c使用標準庫的寫的split函數

split函數。

標準串的：

/********************************************
   the tokenize function for std::string
*********************************************/  
#include <string>   
#include <vector>   
#include <iostream>   
using namespace std;   

typedef basic_string<char>::size_type S_T;   
static const S_T npos = -1;   

////trim指示是否保留空串，默認爲保留。   
vector<string> tokenize(const string& src, string tok,     

bool trim=false, string null_subst="")   
{   
if( src.empty() || tok.empty() ) throw "tokenize: empty
string\0";   

vector<string> v;   
S_T pre_index = 0, index = 0, len = 0;   
while( (index = src.find_first_of(tok, pre_index)) !=   

npos )   
{   
  if( (len = index-pre_index)!=0 )   
    v.push_back(src.substr(pre_index, len));   
  else if(trim==false)   
    v.push_back(null_subst);   
   pre_index = index+1;   
}   
string endstr = src.substr(pre_index);   
if( trim==false ) v.push_back( endstr.empty()?   

null_subst:endstr );   
else if( !endstr.empty() ) v.push_back(endstr);   
return v;   
}   
////使用一個完整的串delimit（而不是其中的

某個字符）來分割src串,沒有trim選項，即嚴格分割。

vector<string> split(const string& src, string delimit,   

string null_subst="")   
{   
if( src.empty() || delimit.empty() ) throw "split:
empty string\0";   

vector<string> v;   
S_T deli_len = delimit.size();   
long index = npos, last_search_position = 0;   
while( (index=src.find(delimit,   

last_search_position))!=npos )   
{   
  if(index==last_search_position)   
    v.push_back(null_subst);   
  else  
    v.push_back( src.substr(last_search_position, index-   

last_search_position) );   
   last_search_position = index + deli_len;   
}   
string last_one = src.substr(last_search_position);   
v.push_back( last_one.empty()? null_subst:last_one );   
return v;   
}   
//test
int main(void)   
{   
string src = ",ab,cde;,,fg,," ;   
string tok = ",;" ;   

vector<string> v1 = tokenize(src, tok ,true);   
vector<string> v2 = tokenize(src, tok ,false,   

"<null>");   

cout<<"-------------v1:"<<endl;   
for(int i=0; i<v1.size();i++)   
{   
   cout<<v1[i].c_str()<<endl;   
}   

cout<<"-------------v2:"<<endl;   
for(int j=0; j<v2.size();j++)   
{   
   cout<<v2[j].c_str()<<endl;   
}   

try{   

   string s = "######123#4###56########789###";   
   string del = "";//"###";   
   vector<string> v3 = split(s, del, "<null>");   
   cout<<"-------------v3:"<<endl;   
  for(int k=0; k<v3.size();k++)   
   {   
    cout<<v3[k].c_str()<<endl;   
   }   
}   
catch (char *s) {   
   cout<<s<<endl;   
}   

return 0;   
}