一个例题编译老提示错误
#include <iostream>
#include <string>
int main()
{
using namespace std;
string s1="Penguin";
string s2,s3;
cout<<"You can assign one string object to another:s2=s1\n";
s2=s1;
cout<<"s1: "<<s1<<",s2: "<<s2<<endl;
cout<<"You can assign a C-style string to a string object.\n";
cout<<"s2=\"buzzard\"\n;
s2="buzzard";
cout<<"s2: "<<s2<<endl;
cout<<"You can concatenate strings:s3=s1+s2\n";
s3=s1+s2;
cout<<"s3: "<<s3<<endl;
cout<<"You can append strings.\n";
s1+=s2;
cout<<'s1+=s2 yields s1= "<<s1<<endl;
s2+="for a day"; //提示这行有问题 我是照书本的
cout<<"s2+= \"for a day\" yields s2= "<<s2<<endl;
return 0;
}
[解决办法]

#include <iostream>
#include <string>
int main()
{
using namespace std;
string s1="Penguin";
string s2,s3;
cout<<"You can assign one string object to another:s2=s1\n";
s2=s1;
cout<<"s1: "<<s1<<",s2: "<<s2<<endl;
cout<<"You can assign a C-style string to a string object.\n";
cout<<"s2=\"buzzard\"\n;//cout<<"s2=\"buzzard\"\n";
s2="buzzard";
cout<<"s2: "<<s2<<endl;
cout<<"You can concatenate strings:s3=s1+s2\n";
s3=s1+s2;
cout<<"s3: "<<s3<<endl;
cout<<"You can append strings.\n";
s1+=s2;
cout<<'s1+=s2 yields s1= "<<s1<<endl;//cout<<"s1+=s2 yields s1= "<<s1<<endl;
s2+="for a day";   //提示这行有问题 我是照书本的
cout<<"s2+= \"for a day\" yields s2= "<<s2<<endl;
return 0;
}