【C++】字符串和数字的相互转化（借助STL）

#include <iostream>
#include <sstream>

int main()
{
    string str = "12 3.14";
    istringstream in(str);
    int v1;
    double v2;
    in >> v1 >> v2;
    cout << "v1=" << v1 << " ,v2=" << v2 << endl;
    return 0;
}

#include <iostream>
#include <sstream>

int main()
{
    int v1 = 12;
    float v2 = 2.14f;
    double v3 = 3.1415926;
    long long v4 = 0x0123456789ABCDEF;
    ostringstream out;
    out << v1 << " "
        << v2 << " "
        << v3 << " "
        << hex << uppercase << v4;
    cout << "str=" << out.str() << endl;
    return 0;
}