改错题<<求大神<<求指教<<大神当练手吧<<--我是一个渣渣π—π

#include<iostream>
#include<string>
using namespace std;
class Student
{
public:
Student(string a,int b,char c)
{
name=a;
age=b;
sex=c;
}
Student()
{}
void print()
{
cout<<"name:"<<name<<"age:"<<age<<"sex:"<<sex<<endl;
}
friend student1(string a,int b,char c,string d);
private:
int age;
string name;
char sex;
};
class student1:public Student
{
public:
student1(string a,int b,char c,string d):Student(a,b,c),addr(d)
void show()
{
Student::print();
cout<<"address"<<addr<<endl;
}
private:
string addr;
};
int main()
{
student1 jim("Jim",18,'b',"china");
jim.show();
Student tom("tom",18,'b');
tom.print();
return 0;
}

这是《C/C++程序设计教程--面向对象分册（第二版）》第二章课后的改错。

#include<iostream>
using namespace std;
class A{
public:
void fun()
{cout<<"a.fun"<<endl;}
};
class B{
public:
void fun(){cout<<"b.fun"<<endl;}
void gun(){cout<<"b.gun"<<endl;}};
class C:public A,public B{
private:
int b;
public:
void gun(){cout<<c.fun<<endl;}
};
int main()
{
C obj;
obj.fun();
obj.gun();
return 0;
}

大家都来讨论讨论也好……

求回复……
如有大神请顺便给个思路，额，错在那里……

第二个已出求一三。求大神继续