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 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.
What is the result of adding an integer to a pointer?
- It causes a compilation error.
- It increments the integer.
- It increments the pointer.
- It multiplies the integer.
Adding an integer to a pointer in C increments the pointer by the product of the integer and the size of the data type pointed to. It does not increment the integer itself. If the result is outside the valid memory range, it can lead to undefined behavior.
Using pointers to structures can lead to more efficient use of ________.
- Data
- Memory
- Storage
- Variables
Pointers to structures in C can lead to more efficient use of storage, as they enable you to manipulate and access the structure's data directly in memory, reducing the need for copying data.
The ________ statement in C is used to execute a block of code only when a specific condition is true.
- For Loop
- While Loop
- If Statement
- Do-While Loop
The correct option is (c) If Statement. In C, the 'if' statement is used to execute a block of code only when a specific condition is true. If the condition is false, the code inside the 'if' block is skipped.
When an array is passed to a function, it is actually passing the ________ of the first element.
- Address
- Copy
- Reference
- Value
When you pass an array to a function in C, you are actually passing the address (pointer) of the first element of the array. This allows the function to access and modify the original array.
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.