#include <iostream>
#include <string>
#include <conio.h>
std::string s1 = "hello";  //全局
int main(){
    std::string s2 = "world"; //局部
    std::cout<<s1<<" "<<s2<<std::endl;
    int s1 = 42;  //局部+隐式全局
    std::cout<<s1<<" "<<s2<<std::endl;
    getch();
    return 0;
}

#include <iostream>
#include <string>
#include <conio.h>
int i = 42;
int main(){
    int i = 100,sum = 0;
    for(int i = 0;i!=10;++i)
            sum += i;
    std::cout<<i<<" "<<sum<<std::endl;
    getch();
    return 0;
}

#include <iostream>
#include <string>
#include <conio.h>
using std::cin;
using std::string;
using std::cout;
int main(){
    string s;
    cin>>s;
    cout<<s;
    getch();
    return 0;
}

#include <iostream>
#include <string>
#include <conio.h>
using std::cin;
using std::string;
using std::cout;
using std::endl;
int main(){
    string st("The expense of spirit\n");
    cout<<"The size of "<<st<<"is"<<st.size()
               <<" characters,including the newline"<<endl;
    getch();
    return 0;
}