Here is a listing of C++ interview questions on “Header Files Usage” along with answers, explanations and/or solutions:
1. What is the user-defined header file extension in c++?
a) cpp
b) h
c) hf
d) none of the mentioned
View Answer
Explanation: None.
2. Which of the following keyword is used to declare the header file?
a) include
b) exclude
c) string
d) namespace
View Answer
Explanation: The include keyword is used to include all the required things to execute the given code in the program.
3. Identify the incorrect statement.
a) iostream is a standard header and iostream.h is a non-standard header
b) iostream is a non-standard header and iostream.h is a non-standard header
c) iostream is a standard header and iostream.h is a standard header
d) none of the mentioned
View Answer
Explanation: The iostream.h is used in the older versions of c++ and iostream is evolved from it in the std namespace.
4. What does a default header file contain?
a) prototype
b) implementation
c) declarations
d) none of the mentioned
View Answer
Explanation: In the header file, we define something that to be manipulated in the program.
5. What is the output of this program?
#include <iostream>using namespace std;
int main()
{char name[30];
cout << "Enter name: ";
gets(name);
cout << "Name: ";
puts(name);
return 0;
}
a) jobsjobs
b) jobs
c) compile time error
d) program will not run
View Answer
Explanation: In this program,we need to string header file to run this program.
6. setprecision requires which of the following header file?
a) stdlib.h
b) iomanip.h
c) console.h
d) conio.h
View Answer
Explanation: The iomanip header file is used to correct the precision of the values.
7. Which of the following header file does not exist?
a) <iostream>
b) <string>
c) <sstring>
d) <sstream>
View Answer
Explanation: None.
8. Which of the header file must be included to use stringstream?
a) <iostream>
b) <string>
c) <sstring>
d) <sstream>
View Answer
Explanation: None.
9. Which of the following header files is required for creating and reading data files?
a) ofstream.h
b) fstream.h
c) ifstream.h
d) console.h
View Answer
Explanation: In this fstream.h header file is used for accessing the files only.
10. What is the output of this program?
#include <iostream>#include <stdarg.h>using namespace std;
float avg( int Count, ... )
{va_list Numbers;
va_start(Numbers, Count);
int Sum = 0;
for (int i = 0; i < Count; ++i)
Sum += va_arg(Numbers, int);
va_end(Numbers);
return (Sum/Count);
}int main()
{float Average = avg(10, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
cout << Average;
return 0;
}
a) 4
b) 5
c) 6
d) compile time error
View Answer
Explanation: In this program, we are finding the average of first 10 numbers using stdarg header file
Output:
$ g++ std.cpp $ a.out 4
Sanfoundry Global Education & Learning Series – C++ Programming Language.
