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.
Why might a programmer choose to use an array of structures in a C program?
- To create global variables
- To perform text formatting
- To sort data
- To store related data efficiently
Programmers use arrays of structures to efficiently manage and organize related data.
The ______ stream in C is used for unbuffered error messages.
- stderr
- stdout
- printf
- ferror
The correct option is a) stderr. The stderr stream is used for unbuffered error messages in C programs.
When defining a structure in C, memory is not allocated until an ________ of the structure is created.
- array
- function
- instance
- pointer
In C, memory for a structure is not allocated until an instance of the structure is created. An instance represents a specific object based on the structure's definition.
You're working on an embedded system with limited memory. What feature of C would you use to efficiently pack multiple flags into a single byte?
- Bit fields
- Pointers
- Inline functions
- Function pointers
Option A, "Bit fields," is the correct choice. Bit fields allow you to efficiently pack multiple boolean flags into a single byte, which is essential in resource-constrained embedded systems, helping to save memory. Bit fields provide control over the size and alignment of data within a structure, allowing you to use memory more efficiently. Other options are not typically used for this purpose and may not offer the same level of memory optimization. Bit fields are an important concept for embedded systems programming.
In a large C program, you notice that a variable is being used in multiple functions but is not behaving as expected. What could be the potential issue regarding the scope of the variable?
- The variable is a global variable
- The variable is a local variable
- The variable is a static variable
- The variable is an automatic variable
The potential issue with the variable not behaving as expected could be that it is a global variable. Global variables have a larger scope and can be modified by multiple functions, which may lead to unintended changes. It's important to be cautious when using global variables in large programs. Static variables retain their values but have a limited scope, making them less likely to cause scope-related issues. Automatic and local variables are confined to individual functions and are less likely to impact other parts of the program.
The fseek function allows for ________ access of data within a file.
- random
- direct
- sequential
- indexed
The correct option is sequential. The fseek() function, when used with SEEK_SET, SEEK_CUR, or SEEK_END, allows for sequential access to data within a file. It enables you to move the file pointer forward or backward, or directly to the end of the file, facilitating sequential data access.
In C, what is the relation between the addresses of consecutive elements of an array of type 'int'?
- The addresses are consecutive with a difference of 1
- The addresses are consecutive with a difference of 2
- The addresses are consecutive with a difference of 4
- The addresses are random and not related
In C, the addresses of consecutive elements of an array of type 'int' are typically consecutive with a difference of 4, as 'int' data type is usually 4 bytes in size. This allows for efficient traversal and indexing.
In a C program that manipulates a large dataset, you observe that the performance is significantly reduced when passing data between functions. How could pointers be used to improve the performance?
- Pointers can be used to create additional datasets.
- Pointers can be used to pass data by reference.
- Pointers can be used to pass data by value.
- Pointers can't improve performance in this scenario.
Pointers can be used to pass data by reference, which avoids the overhead of copying large datasets, improving performance in data manipulation tasks.