C++ Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to C++ Framework. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - What is the output of the following program?

#include<iostream>

using namespace std;
class abc { 
   void f();
   void g();
   int x;
};

main() {
   cout<<sizeof(abc)<<endl;
}

A - 12

B - 4

C - 8

D - Compile error

Answer : B

Explaination

Only the class member variables constitutes as the size of the class or its object.

#include<iostream>

using namespace std;
class abc { 
   void f();
   void g();
   int x;
};
main() {
   cout<<sizeof(abc)<<endl;
}

Q 2 - Which data type can be used to hold a wide character in C++?

A - unsigned char;

B - int

C - wchar_t

D - none of the above.

Answer : C

Explaination

wchar_t is the data type using which we can hold Unicode characters.

Q 3 - In the following program f() is overloaded.

void f(int x) {

}

int f(signed x) { 
   return 1;
}

main() {

}

A - True

B - False

Answer : B

Explaination

No, as both the functions arguments is same and compiler ignores return type to consider overloading though different in return type.

Answer : A

Explaination

There are no keywords in C++ such as abstract and interface.

Q 5 - Which operator is used to resolve the scope of the global variable?

A - −>

B - .

C - *

D - ::

Answer : D

Explaination

Scope resolution operator is used to resolve for the global scope of a variable if the local and global variables conflict by name.

Q 6 - An array can be passed to the function with call by value mechanism.

A - True

B - False

Answer : B

Explaination

An array never is passed with call by value mechanism

Q 7 - What is the output of the following program?

#include<iostream>

using namespace std;
main() { 
   int x = 5;

   if(x==5) {	
      if(x==5) break;
      cout<<"Hello";
   } 

   cout<<Hi; 
}

A - Compile error

B - Hi

C - HelloHi

D - Hello

Answer : A

Explaination

compile error, keyword break can appear only within loop/switch statement.

#include<iostream>

using namespace std;
main() { 
   int x = 5;

   if(x==5) {	
      if(x==5) break;
      cout<<"Hello";
   } 

   cout<<Hi; 
}

Q 8 - What is the size of the following union definition?

#include<iostream>

using namespace std;
main() {
   union abc { 
      char a, b, c, d, e, f, g, h; 
      
      int i;
   };
   cout<<sizeof(abc);
}

A - 1

B - 2

C - 4

D - 8

Answer : C

Explaination

union size is biggest element size of it. All the elements of the union share common memory.

#include<iostream>

using namespace std;
main() {
   union abc { 
      char a, b, c, d, e, f, g, h; 
      
      int i;
   };
   cout<<sizeof(abc);
}

Q 9 - Choose the invalid identifier from the below

A - Int

B - bool

C - DOUBLE

D - __0__

Answer : B

Explaination

bool is the reserved keyword and cannot be used an identifier name.

Q 10 - Does both the loops in the following programs prints the correct string length?

#include<iostream>

using namespace std;
main() {
   int i;
   
   char s[] = "hello";

   for(i=0; s[i]; ++i);
      cout<<i<<endl;

   i=0; 
   
   while(s[i++]);
      cout<<i;
}

A - Yes, both the loops prints the correct length

B - Only for loop prints the correct length

C - Only while loop prints the correct length

D - Compile error in the program.

Answer : B

Explaination

In while loop 'i' gets incremented after checking for '\0', hence giving 1 more than the length.

#include<iostream>

using namespace std;
main() {
   int i;
   
   char s[] = "hello";

   for(i=0; s[i]; ++i);
      cout<<i<<endl;

   i=0;
   
   while(s[i++]);
      cout<<i;
}
cpp_questions_answers.htm
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