打印結構成員

Question

#include <iostream> 
using namespace std; 

struct Person { 
    string first_name; 
    string last_name; 
}; 

int main() { 
    Person a; 
    a.first_name = "foo"; 
    a.last_name = "bar"; 
    cout << a.first_name << " " << a.last_name; 
    return 0; 
} 

給出錯誤：

binary '<<' : no operator found which takes a right-hand operand of 
type 'std::string' (or there is no acceptable conversion) 

爲什麼會發生？

Answer 1

正如其他人在評論中提到，你需要包括string：

#include <iostream> 
#include <string> 
using namespace std; 

struct Person { 
    string first_name; 
    string last_name; 
}; 

int main() { 
    Person a; 
    a.first_name = "foo"; 
    a.last_name = "bar"; 
    cout << a.first_name << " " << a.last_name; 
    return 0; 
}