How can double pointers be used in dynamic memory allocation in C?
- To allocate multi-dimensional arrays
- To create pointer arrays
- To manage pointer arithmetic
- To pass a pointer to a pointer
Double pointers are used in dynamic memory allocation when you need to pass a pointer to a pointer (to allocate and manage multi-dimensional arrays) or create arrays of pointers. They provide an extra level of indirection, which is beneficial for managing memory efficiently.
What is the time complexity of the linear search algorithm in the worst case?
- O(1)
- O(log n)
- O(n)
- O(n^2)
The linear search algorithm has a worst-case time complexity of O(n) because in the worst scenario, it needs to iterate through the entire array to find the target element.
In C programming, what is a common use case for having an array of structures?
- Storing data in a linked list.
- Storing data with different structures.
- Storing multiple records of the same type.
- Storing unrelated data types together.
A common use case for having an array of structures is to store multiple records of the same type. This allows you to create collections of related data with the same structure, such as a list of students' information or employee records.
What is the purpose of using pointers to structures in C programming?
- To access structure members
- To create a new structure
- To declare a structure
- To store an integer
Pointers to structures are used to access and manipulate individual members of a structure.
What is the primary purpose of using pointers in a C function?
- To allocate memory dynamically
- To execute loops
- To perform arithmetic operations
- To store character data
Pointers in C allow you to allocate memory dynamically. They are often used to work with data structures, dynamic memory allocation, and creating flexible functions.
Which function is used to close a file that has been opened using fopen?
- fclose
- fopen
- fread
- fwrite
The fclose function is used to close a file that has been opened using fopen. This is important to release system resources and ensure data is properly saved.
When would it be beneficial to use a function pointer instead of a direct function call?
- Dynamically choosing a function to execute
- Enhancing compile-time error checking
- Reducing code complexity
- Simplifying code structure
Using a function pointer is beneficial when you need to dynamically choose a function to execute at runtime. It offers flexibility and is useful in various scenarios.
What is the time complexity of the bubble sort algorithm in the best case?
- O(1)
- O(log n)
- O(n)
- O(n^2)
The best-case time complexity of the bubble sort algorithm is O(n) when the array is already sorted, and no swaps are required during the pass.
When declaring a variable in C, what does the 'static' keyword do to the variable's lifetime?
- Doesn't affect it
- Extends it
- Initializes it
- Shortens it
The 'static' keyword in C extends the lifetime of a variable, allowing it to retain its value between function calls, making it suitable for data that persists.
You're developing an embedded system with limited memory and need to define several constants representing the states of a system. Which C construct would be most appropriate to use?
- Using functions
- Using global variables
- Using local variables
- Using macros
In an embedded system with limited memory, using macros would be most appropriate for defining constants as they are preprocessor directives and are more memory-efficient than global or local variables. Functions are not used for constants.