Conversion Operators(C++ Programming ) Questions and answers for exam Preparation

Question 1.

Pick out the correct syntax of operator conversion.

operator float()const
operator float()const
operator const
None of the mentioned

Explanation:-

Answer: Option A. -> operator float()const

None.

Question 2.

How types are there in user defined conversion?

1
2
3
4

Explanation:-

Answer: Option B. -> 2

There are two types of user-defined conversions.They are conversion by constructor,

Conversion functions.

Question 3.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
int main()
4.
{
5.
double a = 21.09399;
6.
float b = 10.20;
7.
int c ;
8.
c = (int) a;
9.
cout

2110
1210
21
None of the mentioned

Explanation:-

Answer: Option A. -> 2110

In this program, we casted the data type to integer.
Output:
$ g++ con5.cpp
$ a.out
2110

Question 4.

What is the output of this program?

1.
#include
2.
#include
3.
using namespace std;
4.
class test
5.
{
6.
public:
7.
operator string ()
8.
{
9.
return "Converted";
10.
}
11.
};
12.
int main()
13.
{
14.
test t;
15.
string s = t;
16.
cout

converted
error
run time error
None of the mentioned

Explanation:-

Answer: Option A. -> converted

In this program, We casted the string to the object of the class.
Output:
$ g++ con4.cppp
$ a.out
converted

Question 5.

What is the output of this program?

1.
#include
2.
#include
3.
using namespace std;
4.
class Complex
5.
{
6.
private:
7.
double real;
8.
double imag;
9.
public:
10.
Complex(double r = 0.0, double i = 0.0) : real(r), imag(i)
11.
{}
12.
double mag()
13.
{
14.
return getMag();
15.
}
16.
operator double ()
17.
{
18.
return getMag();
19.
}
20.
private:
21.
double getMag()
22.
{
23.
return sqrt(real * real + imag * imag);
24.
}
25.
};
26.
int main()
27.
{
28.
Complex com(3.0, 4.0);
29.
cout

5 5
4 5
6 6
None of the mentioned

Explanation:-

Answer: Option A. -> 5 5

In this program, we are calculating the magnitude value by two ways.
Output:
$ g++ con3.cpp
$ a.out
55

Question 6.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
class sample
4.
{
5.
public:
6.
sample(int i) : m_i(i) { }
7.
public:
8.
int operator()(int i = 0) const
9.
{
10.
return m_i + i;
11.
}
12.
operator int () const
13.
{
14.
return m_i;
15.
}
16.
private:
17.
int m_i;
18.
friend int g(const sample&);
19.
};
20.
int f(char c)
21.
{
22.
return c;
23.
}
24.
int main()
25.
{
26.
sample f(2);
27.
cout

3
4
5
None of the mentioned

Explanation:-

Answer: Option B. -> 4

In this program, we are adding its value with it itself, So only we got the output as 4.
Output:
$ g++ con1.cpp
$ a.out
4

Question 7.

How many parameters does a conversion operator may take?

0
1
2
as many as possible

Explanation:-

Answer: Option A. -> 0

None.

Question 8.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
class sample1
4.
{
5.
float i, j;
6.
};
7.
class sample2
8.
{
9.
int x, y;
10.
public:
11.
sample2 (int a, int b)
12.
{
13.
x = a;
14.
y = b;
15.
}
16.
int result()
17.
{
18.
return x + y;
19.
}
20.
};
21.
int main ()
22.
{
23.
sample1 d;
24.
sample2 * padd;
25.
padd = (sample2*) &d;
26.
cout 27.
return 0;
28.
}

20
runtime error
random number
c or b

Explanation:-

Answer: Option D. -> c or b

As it assigns to a reference to an object of another incompatible type using explicit type-casting.
Output:
$ g++ con.cpp
$ a.out
14032334

Question 9.

Why we use the "dynamic_cast" type conversion?

result of the type conversion is a valid
result of the type conversion is a valid
result of the type conversion is a invalid
None of the mentioned

Explanation:-

Answer: Option A. -> result of the type conversion is a valid

It is used to check that operators and operands are compatible after conversion.

Question 10.

What is the return type of the conversion operator?

void
int
float
no return type

Explanation:-

Answer: Option D. -> no return type

Conversion operator doesn't have any return type not even void.