string 总结

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void string_replace(string & bigstr,const string &srcstr,const string& decstr)
{
string::size_type pos = 0;
string::size_type strlen =srcstr.size();
string::size_type declen =decstr.size();

while( (pos= bigstr.find(srcstr,pos)) != string::npos)
{
bigstr.replace(pos,strlen +5,decstr); // 这个是用decstr 代替多少个字符，无论多少个字符，换成的都是decstr。
pos += declen;
}
}

#ifdef _FINDFIRST_
const string str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
void main(void)
{
string str2="/*------------jing   ----   peng   */";
string::size_type pos = str2.find_first_of(str);
if ( pos == string::npos)
{
  cout<<"not find the str"<<endl;
}
string::size_type endpos = str2.find_last_of(str);
if ( endpos == string::npos)
{
  cout<<"not find the str at end"<<endl;
}
string str3 = str2.substr(pos,endpos-pos+1 );
cout<<str3<<endl;
getch();
}

int string2int(const string & str)
{
return atoi(str.c_str());
}

double string2double(const string & str)
{
return atof(str.c_str());
}

#include <iostream>
#include <sstream>
#include <string>

template <class T>
void convertFromString(T &, const std::string &);

int main()
{
std::string s("123");

// Convert std::string to int
     int i = 0;
convertFromString(i,s);
     std::cout << i << std::endl;
// Convert std::string to double
double d = 0;
convertFromString(d,s);
     std::cout << d << std::endl;
return 0;
}

template <class T>
void convertFromString(T &value, const std::string &s)
{
std::stringstream ss(s);
ss >> value;
}
#endif