这C++代码为啥没有输出呢？

#include
#include
using namespace std;
class Animal
{private: std::string name;
int size;
int weight;
public:
string a;
int b;
int c;
Animal(string a,int b,int c)
{ name=a; size=b; weight=c; };
int na() {cout<<"动物名字是："<<name<<endl<<"身体大小："<<b<<endl<<"体重是："<<c<<endl; return 0; };
void run() { cout<<name<<"可以跑"<<endl; };void zou() { cout<<name<<"可以走"<<endl; };};
class Bird:public Animal{public: int yumao; int chibang;
Bird(string x1,int x2,int x3,int x4,int x5): Animal( a,b,c) { yumao=x4; chibang=x5; }
void fly() {cout<<a<<"有羽毛和翅膀，可以飞"<<endl; };};
int main(){
Bird n("鸟",65,44,11,12);
n.na(); n.run(); n.zou(); n.fly(); return 0;}

问题比较多，这么改就可以了。

class Animal
{ 
public:
std::string name;
int size;
int weight;
Animal(string a,int b,int c)
{ name=a; size=b; weight=c; };
int na() {cout<<"动物名字是："<<name<<endl<<"身体大小："<<size<<endl<<"体重是："<<weight<<endl; return 0; };
void run() { cout<<name<<"可以跑"<<endl; };void zou() { cout<<name<<"可以走"<<endl; };};
class Bird:public Animal{public: int yumao; int chibang;
Bird(string x1,int x2,int x3,int x4,int x5): Animal( x1,x2,x3) { yumao=x4; chibang=x5; }
void fly() {cout<<name<<"有羽毛和翅膀，可以飞"<<endl; };};
int main()
{
Bird n("鸟",65,44,11,12);
n.na(); n.run(); n.zou(); n.fly(); 
return 0;
}