What is the significance of the size_t return type in the fwrite function?
- It determines the file's size.
- It indicates the file's creation date.
- It is used to specify the file mode.
- It represents the number of items written to the file.
The size_t return type in the fwrite function signifies the number of items successfully written to the file. This is important for checking the success of the write operation.
What is the difference between malloc and calloc in terms of initialization of the allocated memory?
- Calloc initializes memory to an undetermined value.
- Calloc initializes memory to zero.
- Malloc initializes memory to an undetermined value.
- Malloc initializes memory to zero.
Malloc initializes memory to an undetermined value, while calloc initializes memory to zero. This difference is important when you want to ensure that allocated memory is initialized in a specific way.
Which operator is used to check if two values are equal?
- !=
- =
- ==
- ===
In C, the '==' (double equals) operator is used to check if two values are equal. It is a comparison operator, while '=' is an assignment operator. Confusing these can lead to unintended consequences, making it crucial to understand their distinct purposes in programming.
What string handling function is used to concatenate two strings in C?
- sprintf()
- strcat()
- strcmp()
- strcpy()
In C, the strcat() function is used to concatenate two strings. It appends the characters of the second string to the end of the first string.
In a project involving real-time systems, you notice that different modules use different naming conventions for the same data type. What feature of C can help maintain consistency across modules?
- Typedef
- Namespaces
- Code comments
- Function pointers
Option A, "Typedef," is the most suitable choice in this context. By using typedef, you can create consistent, user-friendly names for data types, which helps maintain a unified naming convention across modules in a project. This consistency enhances code readability, reduces errors, and simplifies maintenance. Namespaces are not a feature in C, and other options do not directly address naming convention consistency. Understanding how to use typedef effectively is essential for creating a consistent codebase in C.
How can you redirect error messages in a C program to a file instead of displaying them on the console?
- stderr_redirect()
- errorToFile()
- file_error()
- freopen()
The correct option is freopen(). This function can be used to redirect standard error (stderr) to a file. By using freopen("error.log", "w", stderr), error messages will be written to the specified file instead of the console.
In C, pointers can be used to pass ________ to a function.
- addresses
- constants
- data
- variables
In C, pointers can be used to pass addresses to a function. This allows functions to modify the original data.
To resize a previously allocated memory block, the function ________ is used in C.
- calloc()
- free()
- malloc()
- realloc()
To resize a previously allocated memory block in C, the function realloc() is used. It allows you to change the size of the memory block while preserving the existing data. malloc() and calloc() are used for initial memory allocation, and free() deallocates memory.
How can function pointers be used to implement callbacks in C?
- Function pointers are not used for callbacks
- Function pointers are used for dynamic linking
- Function pointers are used to implement recursion
- Function pointers can be used to pass a function as an argument to another function
Function pointers in C can be used to implement callbacks. By passing a function pointer as an argument to another function, you can dynamically specify the function to be called, enabling flexibility in callback implementations.
When a value is passed to a function by value, what is passed to the function?
- A copy of the value
- A pointer to the value
- A reference to the value
- The memory address of the value
When a value is passed to a function by value, a copy of the actual value is passed to the function. Changes made to the parameter inside the function do not affect the original value.