Lecture2

#include <iostream>
using namespace std;
int main(){


    cout<<"Hello world"<<endl;
    return 0;

}
#include <iostream>
using namespace std;
int main(){

int a =3;
int b=4;
int c;
cout<<a+b<<endl<<"a+b";
cout<<a+b;
cout<<endl;
cout<<"a+b";
return 0;

}