38 Lecture

1. What is a user-defined manipulator in C++? A. A function that modifies the input of a stream B. A function that modifies the output of a stream C. A function that sorts an array of integers D. A function that calculates the factorial of a number

Answer: B

2. How are user-defined manipulators defined in C++? A. As member functions of a class B. As global functions outside of any class C. As friend functions of a class D. As virtual functions of a class

Answer: B

3. What is the purpose of a user-defined manipulator? A. To read input from a stream B. To modify the output of a stream C. To create a new stream object D. To delete data from a stream

Answer: B

4. Which operator is used to call a user-defined manipulator? A. >> B. << C. + D. -

Answer: B

5. What is the syntax for defining a user-defined manipulator function? A. void manipulator(ostream& stream); B. ostream& operator<<(ostream& stream, manipulator fn); C. int manipulator(int x); D. void operator<<(ostream& stream, manipulator fn);

Answer: B

6. What is the return type of a user-defined manipulator function? A. void B. int C. char D. ostream&

Answer: D

7. What is the purpose of the std::setw() function? A. To set the width of the output field B. To set the precision of the output field C. To set the fill character of the output field D. To set the format flags of the output field

Answer: A

8. What is the purpose of the std::setfill() function? A. To set the width of the output field B. To set the precision of the output field C. To set the fill character of the output field D. To set the format flags of the output field

Answer: C

9. What is the purpose of the std::setprecision() function? A. To set the width of the output field B. To set the precision of the output field C. To set the fill character of the output field D. To set the format flags of the output field

Answer: B

10. Which header file must be included to use user-defined manipulators in C++? A. <string> B. <fstream> C. <iostream> D. <iomanip>

Answer: D

1. What is a user-defined manipulator in C++? Answer: A user-defined manipulator is a function that modifies the output of a stream in a customized way.

2. How are user-defined manipulators defined in C++? Answer: User-defined manipulators are defined as global functions outside of any class.

3. What is the syntax for calling a user-defined manipulator? Answer: The syntax for calling a user-defined manipulator is to use the insertion operator (<<) followed by the manipulator function name.

4. What is the purpose of std::setw() function in C++? Answer: The std::setw() function is used to set the width of the output field.

5. What is the return type of a user-defined manipulator function in C++? Answer: The return type of a user-defined manipulator function is ostream&.

6. How can we define a manipulator that sets the precision of floating-point values in C++? Answer: We can define a manipulator that sets the precision of floating-point values using the std::setprecision() function.

7. What is the purpose of the std::setfill() function in C++? Answer: The std::setfill() function is used to set the fill character of the output field.

8. What is the purpose of std::left and std::right manipulators in C++? Answer: std::left and std::right manipulators are used to set the alignment of the output field to the left or right, respectively.

9. Can we chain multiple user-defined manipulators together in C++? Answer: Yes, we can chain multiple user-defined manipulators together using the insertion operator (<<).

10. What is the header file that must be included to use user-defined manipulators in C++? Answer: The header file that must be included to use user-defined manipulators in C++ is <iomanip>.

In C++, a user-defined manipulator is a function that modifies the output of a stream in a customized way. We can define our own manipulator functions as global functions outside of any class. These manipulator functions take a reference to an ostream object as input and return a reference to the same object. One common use of user-defined manipulators is to control the formatting of output. For example, we can define a manipulator that sets the width of the output field using the std::setw() function. We can also define a manipulator that sets the precision of floating-point values using the std::setprecision() function. Another use of user-defined manipulators is to set the alignment of output fields. The std::left and std::right manipulators are used to set the alignment of the output field to the left or right, respectively. We can also define our own manipulators to set the fill character of the output field using the std::setfill() function. We can chain multiple user-defined manipulators together using the insertion operator (<<). For example, we can define a manipulator that sets the width of the output field and another manipulator that sets the precision of floating-point values, and then chain them together to output a formatted floating-point number. User-defined manipulators can make our code more readable and reusable. They allow us to separate the formatting logic from the rest of the code, which can simplify the code and make it easier to maintain. They also make it easier to apply the same formatting to multiple output streams throughout our program. To use user-defined manipulators, we must include the <iomanip> header file.