Thread: Help needed on constructors!

Modify the default constructor to that the data member is initialized to zero in the initialization list. Provide a second constructor to allow "Integer" objects to be created and initialized with a value.
In your test program, write a function that takes an Integer object as an argument, first by value and then by reference. What do you see printed from constructors and destructors when the function is called? Explain what you understand in a few statements.

Code:

#include <iostream>
using namespace std;
//Muhammad Danish
//67
//SEECS

class R{
public:
    int danish1;
    int danish2;
    int danish3;
    R();

R(int a,int b,int c);
};

int main()
{R f;
    cout<<"Danish1="<<f.danish1;
}


R::R(int a=7,int b=9,int c=7){
danish1=a;
danish2=b;
danish3=c;
}

can you differentiate b/w different types of constructors and how they are called??

integer class is R.

Plus what if I want to initialize the integers by zero using default constructor.

To get rid of plagiarism,I named it R instead of Integer and more Danish1,danish2 ,Danish 3 are integers to be initialized first by zero and other two by a value other than zero.

Code:

#include <iostream>
using namespace std;
//Muhammad Danish
//67
//SEECS

class R{
public:
    int danish1;
    int danish2;
    int danish3;
    int danish4;
    R();

R(int l,int w,int h);
};

int main()
{R f();
    cout<<"\n Initialised by zero using default constructor is \n"<<f().danish1;
    
R f2(10,3,6);
cout<<"\nOther by Initialised by value using Initialising list are\n"<<f2().danish2<<f().danish3<<f().danish4;
}


R::R():danish1(0){

cout<<"\nR Default constructor is called\n";
}
R::R(int l=1, int w=2, int h=3): danish2(l),danish3(w),danish4(h)
     {cout<<"\nBox contructor is invoked";
}

dont know what to do now?

what do u mean by default arguments????

Originally Posted by laserlight

Look at this part:

Code:

R::R(int l=1, int w=2, int h=3)

You are saying that if the argument that corresponds to the parameter h is not supplied when this constructor is invoked, then h will default to having a value of 3. Likewise, if the arguments corresponding to both h and w are both not supplied, then w will have default to having a value of 2. If no arguments are supplied, then l will default to having a value of 1.

Problem is, you also declared:

Code:

R();

defining it as:

Code:

R::R():danish1(0){
    cout<<"\nR Default constructor is called\n";
}

So, if you create an object of R without supplying any arguments to its constructor, which constructor should be called? That is an ambiguity there.

Thanks mam.!