What does the 'NULL' pointer represent in C?
- A pointer to a constant value
- A pointer to a non-existent location
- A pointer to the keyboard input
- A pointer to the main function
The 'NULL' pointer in C represents a pointer that doesn't point to any memory location. It's often used to indicate that a pointer is not currently pointing to valid data.
How does using pointers with arrays affect the performance of a C program?
- It always degrades performance
- It can improve performance in some cases
- It has no effect on performance
- It only affects memory usage, not performance
Using pointers with arrays in a C program can actually improve performance in some cases. By using pointers, you can manipulate array elements more efficiently and access them directly, reducing the overhead of array indexing. This can lead to better performance. However, it's essential to use pointers carefully to avoid issues like memory corruption.
When writing data to a text file, which function is used to ensure that the data is written correctly?
- fprintf
- fputc
- fputs
- fwrite
The fprintf function is used to write formatted data to a text file in C. It allows you to specify the format and data to be written, ensuring that the data is written correctly with appropriate formatting.
The ________ sorting algorithm repeatedly steps through the list, compares adjacent elements and swaps them if they are in the wrong order.
- Binary
- Bubble
- Merge
- Quick
The 'Bubble' sorting algorithm repeatedly steps through the list, comparing adjacent elements, and swapping them if they are in the wrong order. It is a simple sorting algorithm but not very efficient for large datasets.
A ________ occurs when a program continues to use a pointer after it has been freed.
- Buffer Overflow
- Dangling Pointer
- Memory Leak
- Segmentation Fault
A Dangling Pointer occurs when a program continues to use a pointer after it has been freed. This can lead to undefined behavior, crashes, or data corruption. It's crucial to avoid using pointers that point to memory that has been deallocated.
Why would you use a pointer to an array instead of a regular array in a function?
- Pointers allow you to modify the original array in a function.
- Pointers allow you to pass arrays to functions without making a copy.
- Pointers are more memory-efficient than regular arrays.
- Pointers provide a way to dynamically allocate memory for arrays.
Using a pointer to an array in a function allows you to pass the array by reference, avoiding the need to make a copy of the array. This is more memory-efficient and allows you to modify the original array within the function.
When working with binary files, the ________ function can be used to read data in a structured manner.
- fread()
- fgets()
- fgetc()
- fscanf()
The correct option is fread(). This function is specifically designed for reading binary data from a file. It takes parameters like the file pointer, size of each element, number of elements, and the destination buffer where the data will be stored. This makes it suitable for structured reading of binary files.
What does the fseek function do in a C program?
- Sets the file position indicator to the beginning
- Moves the file position indicator to the end
- Positions the file pointer to a specified location
- Closes the file
The correct option is c. Positions the file pointer to a specified location. The fseek() function in C is used to set the file position indicator to a specific location within the file, allowing random access and manipulation of file contents.
You're developing a database system and need to frequently update records. What file handling technique would you use to efficiently update specific records without reading the entire file?
- Direct File Updating
- Indexed File Updating
- Random File Updating
- Sequential File Updating
Indexed File Updating would be the most efficient technique for frequently updating specific records in a database system. With an index, the system can quickly locate and update the desired record without the need to read the entire file sequentially. This reduces the time and resources required for updates, making it a suitable choice for scenarios where frequent record updates are a common operation in a database.
In the context of searching algorithms, why might a binary search be preferred over a linear search?
- Binary search guarantees to find the target quickly
- Binary search is always faster
- Binary search requires sorted data
- Binary search works for unsorted data
Binary search is preferred when data is sorted as it allows for efficient searching, while a linear search works for unsorted data.