Namespaces(C++ Programming ) Questions and answers for exam Preparation

Which keyword is used to access the variable in namespace?

using
dynamic
const
static

Explanation:-

Answer: Option A. -> using

None.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
namespace extra
4.
{
5.
int i;
6.
}
7.
void i()
8.
{
9.
using namespace extra;
10.
int i;
11.
i = 9;
12.
cout

9
10
compile time error
none of the mentioned

Explanation:-

Answer: Option A. -> 9

A scope resolution operator without a scope qualifier refers to the global namespace.

Question 3.

What is the output of this program?

1.
#include
2.
using namespace std
3.
namespace space
4.
{
5.
int x = 10;
6.
}
7.
namespace space
8.
{
9.
int y = 15;
10.
}
11.
int main(int argc, char * argv[])
12.
{
13.
space::x = space::y =5;
14.
cout

1015
1510
55
compile time error

Explanation:-

Answer: Option C. -> 55

We are overriding the value at the main function and so we are getting the output as 55.
Output:
$ g++ name4.cpp
$ a.out
55

Question 4.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
namespace Box1
4.
{
5.
int a = 4;
6.
}
7.
namespace Box2
8.
{
9.
int a = 13;
10.
}
11.
int main ()
12.
{
13.
int a = 16;
14.
Box1::a;
15.
Box2::a;
16.
cout

4
13
16
compile time error

Explanation:-

Answer: Option C. -> 16

In this program, as there is lot of variable a and it is printing the value inside the block

because it got the highest priority.
Output:
$ g++ name2.cpp
$ a.out
16

Question 5.

What is the output of these program?

1.
#include
2.
using namespace std;
3.
namespace first
4.
{
5.
int x = 5;
6.
int y = 10;
7.
}
8.
namespace second
9.
{
10.
double x = 3.1416;
11.
double y = 2.7183;
12.
}
13.
int main ()
14.
{
15.
using first::x;
16.
using second::y;
17.
bool a, b;
18.
a = x > y;
19.
b = first::y < second::x;
20.
cout

11
01
00
10

Explanation:-

Answer: Option D. -> 10

We are inter mixing the variable and comparing it which is bigger and smaller and according

to that we are printing the output.
Output:
$ g++ name1.cpp
$ a.out
10

Question 6.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
namespace first
4.
{
5.
int var = 5;
6.
}
7.
namespace second
8.
{
9.
double var = 3.1416;
10.
}
11.
int main ()
12.
{
13.
int a;
14.
a = first::var + second::var;
15.
cout

8.31416
8
9
compile time error

Explanation:-

Answer: Option B. -> 8

As we are getting two variables from namespace variable and we are adding that.
Output:
$ g++ name.cpp
$ a.out
8

Question 7.

Which operator is used to signify the namespace?

conditional operator
ternary operator
scope operator
none of the mentioned

Explanation:-

Answer: Option C. -> scope operator

None.

Question 8.

What is the use of Namespace?

To encapsulate the data
To structure a program into logical units.
Both a and b
none of the mentioned

Explanation:-

Answer: Option B. -> To structure a program into logical units.

The main aim of the namespace is to understand the logical units of the program and to make

the program so robust.

Question 9.

Identify the correct statement.

Namespace is used to group class, objects and functions.
Namespace is used to mark the beginning of the program.
Namespace is used to seperate the class, objects.
None of the above

Explanation:-

Answer: Option A. -> Namespace is used to group class, objects and functions.

Namespace allow you to group class, objects and functions. It is used to divide the global

scope into the sub-scopes.

Question 10.

What is the general syntax for accessing the namespace variable?

namespaceid::operator
namespace,operator
namespace#operator
none of the mentioned

Explanation:-

Answer: Option A. -> namespaceid::operator

None.