How to initialize an object of derived class when the derived class and base class both have parameterized constructors?

I am facing problem in initializing objects. Following is a piece of code,

#include <iostream>
#include <conio.h>
using namespace std;

class Base
{
public:
Base(int a)
{
    m_a = a;
}
private:
int m_a;

};

class Derived:public Base
{
public:
Derived(char a)
{
    m_a = a;
}
private:
char m_a;开发者_开发知识库

};


void main()
{

_getch();

}

Compiling the above code gives the following error, error C2512: 'Base' : no appropriate default constructor available

I know that since derived class and base class both have only parametrized constructors i need to initialize the base class object in derived class constructor. But i don't know how to do it. Can anyone please tell me as to what is wrong in the above code?

    public:
    Derived(char a):Base(/*int Parameter*/),m_a(a)
    {

    }

After making trails i one more way to initialize the base class too, Following is the code,

#include <iostream>
#include <conio.h>
using namespace std;

class Base
{
public:
Base(int a)
{
    m_a = a;
}
private:
int m_a;

};

class Derived:public Base
{
public:
Derived(int b, char a):Base(b)
{
    m_a = a;
}
private:
char m_a;

};


void main()
{
    Derived d(10,'A');

_getch();

}