#include <iostream>
#include <sstream>
#include <string>
#include <strstream>
using namespace std;
//将整型转换成字符型
string int_to_string(int i)
{
    ostringstream os;
    os<<i;
    return os.str();
}
string int_to_string1(int i)
{
    ostrstream os;
    os<<i;
    return os.str();
}
int main()
{
    cout<<int_to_string(20)<<endl;
    cout<<int_to_string1(20)<<endl;
    return 0;
}