C++ Programming - Functions

#include<iostream.h> 
class IndiaBix
{
    public: 
    int x, y;
    IndiaBix(int xx = 10, int yy = 20)
    {
        x = xx;
        y = yy; 
    }
    void Exchange(int *, int *);
};
int main()
{
    IndiaBix objA(30, 40); 
    IndiaBix objB(50); 
    objA.Exchange(&objA.x, &objB.y); 
    cout<< objA.x << " " << objB.y << endl; 
    return 0;
}
void IndiaBix::Exchange(int *x, int *y)
{
    int t;
    t  = *x;
    *x = *y;
    *y = t ; 
}

#include<iostream.h> 
class BixArray
{
    int Matrix[3][3]; 
    public:
    BixArray()
    {
        for(int i = 0; i<3; i++)
           for(int j = 0; j < 3; j++) 
              Matrix[j][i] = i + j; 
    }
    void Display(void)
    {
        for(int i = 0; i < 3; i++)
           for(int j = 0; j < 3; j++) 
              cout<< Matrix[j][i] << " "; 
    } 
}; 
int main()
{
    BixArray objBix;
    objBix.Display();
    return 0; 
}

#include<iostream.h> 
class IndiaBix
{
    int x, y, z; 
    public:
    void Apply(int xx = 12, int yy = 21, int zz = 9)
    {
        x = xx;
        y = yy += 10;
        z = x -= 2;
    }
    void Display(void)
    {
        cout<< x << " " << y << endl; 
    } 
    void SetValue(int xx, int yy)
    {
        Apply(xx, 0, yy);
    }
};
int main()
{
    IndiaBix *pBix= new IndiaBix;
   (*pBix).SetValue(12, 20);
    pBix->Display();
    delete pBix;
    return 0; 
}

#include<iostream.h>
#include<string.h> 
class IndiaBix
{
    char txtMsg[50]; 
    public:
    IndiaBix(char *str = NULL)
    {
    if(str != NULL)
       strcpy(txtMsg, str);
    }
    int BixFunction(char ch);
};
int IndiaBix::BixFunction(char ch)
{
    static int i = 0;
    if(txtMsg[i++] == ch)
        return strlen((txtMsg + i)) - i;
    else
        return BixFunction(ch);
}
int main()
{
    IndiaBix objBix("Welcome to IndiaBix.com!");
    cout<< objBix.BixFunction('t');
    return 0;
}

#include<iostream.h>
#include<string.h>
#include<malloc.h>
class BixString
{
    char txtName[20]; 
    public:
    BixString(char *txtTemp = NULL)
    {
        if(txtTemp != NULL)
        strcpy(txtName, txtTemp);
    }
    void Display(void)
    {
        cout<<txtName;
    }
};
int main()
{
    char *txtName = (char*)malloc(10);
    strcpy(txtName, "IndiaBIX");
    *txtName = 48;
    BixString objTemp(txtName);
    cout<< sizeof(txtName);
    return 0; 
}