You are developing a library of mathematical functions. How can you design the library to allow users to apply custom operations on data without modifying the library code?
- Use function pointers
- Use inheritance and polymorphism
- Use global variables
- Use the preprocessor macro
Option A is the correct answer. Using function pointers allows users to pass custom functions to the library without modifying the library's code. Option B (inheritance and polymorphism) is a valid design approach but doesn't allow users to apply custom operations easily. Options C and D are not suitable for this purpose.
What is the return type of the fread function in C?
- char
- float
- int
- void
The fread function in C returns an integer, which represents the number of elements successfully read from the file. It's commonly used in binary file I/O to read data into a buffer.
How does the memory alignment of a structure's members affect its total size?
- It aligns the structure members to byte boundaries
- It decreases the total size
- It has no impact on the total size
- It increases the total size
Memory alignment in structures affects the total size by ensuring that structure members are positioned on specific byte boundaries. This alignment is necessary for efficient memory access and to prevent wasted memory.
To write data to a file, the file must be opened in ________ mode.
- w
- r
- a
- write
The correct option is a) w. In C, to write data to a file, the file must be opened in write mode (w).
How can you pass a command line argument to a C program that is meant to be interpreted as an integer?
- Assign the argument to a string variable
- Convert the argument using atoi()
- Use argv[0] to access the argument
- Use scanf to read the argument from the user
To interpret a command line argument as an integer, you should use the atoi() function to convert the string argument to an integer data type.
You are working on an application that requires fast data retrieval times. What method of file access would be most suitable?
- Direct File Access
- Indexed File Access
- Random Access
- Sequential File Access
For fast data retrieval times, Random Access is the most suitable method. Unlike Sequential File Access, which reads data sequentially, and Indexed File Access, which uses an index to locate data, Random Access allows direct access to any part of the file. This is crucial for applications where quick retrieval of specific data is essential, such as databases and real-time systems.
You are developing a contact management system where each contact can have multiple addresses (home, work, etc.). How can you efficiently represent this information using structures?
- By creating a separate database for addresses
- By using an array for each contact
- By using separate variables for each address
- By utilizing a structure to hold multiple addresses within a contact structure
To efficiently represent multiple addresses for each contact, you can use a structure to hold multiple addresses within a contact structure. This approach ensures that each contact can have different types of addresses, such as home and work, making it a practical way to manage contact information.
How can you determine if you have reached the end of a file while reading it in C?
- Check if the file size is zero.
- Count the number of lines in the file.
- Examine the file's creation date.
- Use the feof function to check for end-of-file status.
You can determine if you've reached the end of a file in C by using the feof function, which checks for the end-of-file status of the stream.
What is the scope of a local variable defined inside a function in C?
- Global scope
- Limited to the block
- Limited to the function
- No scope
In C, a local variable defined inside a function has scope limited to that specific function. It cannot be accessed from outside the function.
In a C++ application, you notice that a function is being called with different types of arguments, but there is only one function definition. What feature of C++ could be allowing this behavior?
- Dynamic casting
- Function overloading
- Inheritance and polymorphism
- Operator overloading
The behavior of calling a function with different argument types using a single function definition is achieved through function overloading in C++. This feature allows multiple function definitions with the same name but different parameter types.