C MCQ Practice Test

Q1. What will be the output of the following C code snippet? c #include <stdio.h> int main() { int x = 10; int y = 5; int z = x / y + x % y; printf("%d", z); return 0; }

• A. 3
• B. 2 ✓
• C. 10
• D. 5

Q2. What will be the output of the following C code snippet? c #include <stdio.h> int main() { int x = 5; int y = 10; int z = x + y / 2; printf("%d", z); return 0; }

• A. 10 ✓
• B. 7
• C. 15
• D. 5

Q3. What is the purpose of the !!__attribute__((__packed__))!! directive in C?

• A. It forces the compiler to align struct members to the natural size of their types
• B. It enables the compiler to generate optimized code for the target platform
• C. It instructs the compiler to pack struct members tightly, without padding ✓
• D. It allows the programmer to specify custom memory allocation for variables

Q4. What is the purpose of the 'volatile' keyword in C when used with a global variable?

• A. To ensure thread safety in a multi-threaded environment
• B. To prevent the compiler from optimizing away the variable ✓
• C. To indicate that the variable is used in a signal handler
• D. To specify the variable's storage class

Q5. What is the effect of the "static" keyword when applied to a function in C?

• A. It makes the function thread-safe.
• B. It limits the function's scope to the current file. ✓
• C. It causes the function to be called only once during the program's execution.
• D. It makes the function's local variables retain their values between function calls.

Q6. What is the purpose of the `scanf` format specifier `%p` in C?

• A. Reads a pointer value in hexadecimal format. ✓
• B. Reads a pointer to a character.
• C. Reads a pointer to an integer.
• D. Reads a floating-point number.

Q7. What is the purpose of the "__attribute__((packed))" directive in C?

• A. "__attribute__((packed))" is used to specify that a structure should be aligned on a 4-byte boundary.
• B. "__attribute__((packed))" is used to specify that a structure should not have any padding bytes. ✓
• C. "__attribute__((packed))" is used to specify that a function should be called with a specific calling convention.
• D. "__attribute__((packed))" is used to specify that a variable should be initialized with a specific value.

Q8. What is the purpose of the "static" keyword when used with a function in C?

• A. To make the function thread-safe
• B. To prevent the function from being inlined
• C. To make the function's address unavailable ✓
• D. To make the function's call faster

Q9. In C, what is the purpose of the `__attribute__((packed))` attribute when applied to a struct?

• A. It forces the compiler to use a specific alignment for the struct.
• B. It allows the compiler to optimize the struct layout for better performance.
• C. It tells the compiler to pack the struct members tightly without padding. ✓
• D. It enables the compiler to generate debugging information for the struct.

Q10. Given a C function that uses the `longjmp` function to implement a non-local jump, what is the purpose of the `setjmp` function?

• A. To set up a non-local jump buffer
• B. To restore the state of the program after a longjmp
• C. To save the current state of the program for a later longjmp ✓
• D. To perform a non-local jump without using setjmp

That was just a sample. Sign up to unlock the full question bank with timed tests and certificates.