What is the primary function of pointers in C?
- To manipulate strings
- To perform mathematical operations
- To provide dynamic memory allocation
- To store variables
Pointers in C are primarily used for dynamic memory allocation. They allow you to allocate and deallocate memory at runtime, which is essential for efficient memory usage and data structure implementation.
The ________ loop checks the condition before executing the block of code.
- do-while
- for
- if
- while
The "do-while" loop is used in programming to check the condition after executing the block of code at least once. It guarantees that the loop body is executed at least once, as the condition is evaluated after the first iteration. On the other hand, "for" and "while" loops check the condition before entering the loop, and "if" is used for conditional statements, not loops.
In C, an array name acts as a ________ pointing to the first element of the array.
- label
- pointer
- reference
- variable
In C, an array name is a constant pointer that points to the address of the first element in the array.
A ________ allows multiple variables to share the same memory location.
- Function
- Pointer
- Structure
- Union
A union allows multiple variables to share the same memory location, making it useful for scenarios where different types of data need to occupy the same memory space.
In C, a double pointer is a pointer that points to another ________.
- double
- int
- pointer
- variable
In C, a double pointer is a pointer that points to another pointer. It is used to store the address of a pointer variable.
In C, the ________ function is used to copy a specified number of characters from one string to another.
- memcpy()
- strcpy()
- strncat()
- strncpy()
In C, the strncpy() function is used to copy a specified number of characters from one string to another. Unlike strcpy(), it allows you to specify the maximum number of characters to copy, which helps prevent buffer overflows and enhances program security.
The fread function in C is used to read data from a file and stores the data in the ________.
- Buffer
- Memory
- Stack
- Registers
The fread function in C reads data from a file and stores it in memory, making option b) "Memory" the correct answer.
In a program that processes large amounts of data, what strategy can be used to optimize the performance of loops?
- Loop branching optimization
- Loop indexing optimization
- Loop parallelization
- Loop unrolling
To optimize the performance of loops when processing large data, 'loop unrolling' can be used. Loop unrolling reduces loop overhead and can improve data processing speed.
What is the difference between #include "filename" and #include in C?
- #include "filename" is for standard library files.
- #include "filename" is for user-defined files.
- #include
is for user-defined files. - They are interchangeable and have no difference.
In C, #include "filename" is used for user-defined header files, and #include is used for standard library header files.
In a program that processes large datasets, you notice that reading the data from a file is a performance bottleneck. Which file handling functions could help improve the performance?
- fread() and fwrite()
- fseek() and ftell()
- fprintf() and fscanf()
- fgetc() and fputc()
To improve performance when dealing with large datasets, using fread() and fwrite() for bulk reading and writing of data would be beneficial. The other options involve more granular or formatted I/O operations.
How are strings typically terminated in C?
- With a comma
- With a newline character
- With a null character ( ' ' )
- With a space character
Strings in C are typically terminated with a null character (' ') to indicate the end of the string.
How does the 'extern' keyword affect the scope and lifetime of a variable in C?
- It doesn't affect the scope or lifetime of a variable.
- It extends the scope and lifetime of a variable.
- It extends the scope but reduces the lifetime of a variable.
- It reduces the scope but extends the lifetime of a variable.
In C, the 'extern' keyword extends the scope of a variable but reduces its lifetime. It allows a variable declared outside a function to be used within that function, but the variable's lifetime remains outside the function.