c++ string 转 int longlong float double

隔一段时间不写就忘记函数是什么了，今日记下，以作查询。

#include
using namespace std;
string str;
int aint;
long long alonglong;
float afloat;
double adouble;
int main()
{

    str = "1";
    aint = stoi(str);
    cout<<aint<<endl;

    cout<<~(1<<31)<<endl;
    str = "214748364700";
    alonglong = stoll(str);
    cout<<alonglong<<endl;

    str = "23.4";
    afloat = stof(str);
    cout<<afloat<<endl;

    str = "6718234.32432";
    adouble = stod(str);
    cout<<adouble<<endl;
    return 0;
}