C Programming - MCQ Practice Questions

This involves undefined behavior due to modification of x multiple times without intervening sequence points.

Angle brackets search standard include directories, while quotes search the current directory first, then standard directories.

Integer division truncates the result. $\frac{5}{2}$ = 2 (not 2.5) because both operands are integers.

NULL is a macro (not a keyword) typically defined as (void *)0, and can be used interchangeably with 0 for pointer assignments.

A static variable declared in a block has block scope but static storage duration, persisting between function calls.

arr + 1 points to the second element, so *(arr + 1) dereferences it to give 2.

'inline' is a hint to the compiler suggesting it should inline the function, though the compiler may ignore it.

x++ is post-increment. The current value (10) is printed first, then x is incremented to 11. So output is 10.

'long long' is guaranteed to be at least 64 bits (8 bytes) as per C99 standard.

\t is the escape sequence for horizontal tab. \n is newline, \h and \s are not valid escape sequences.

getchar() reads a single character from standard input and returns it. For strings, fgets() or scanf() is used.

This is the ternary operator. Since 5 < 10 is true, b = 20. If false, b would be 30.

Static variables retain their value between function calls and are initialized only once. They persist for the lifetime of the program.

10 % 3 = 1 (remainder), $\frac{10}{3}$ = 3 (integer division). Output is '1 3'.

volatile tells the compiler that a variable's value can change unexpectedly (e.g., in hardware registers or interrupt handlers), so it should not optimize away repeated reads.

register keyword suggests the compiler to store the variable in CPU register for faster access. Modern compilers often ignore this hint. You cannot take address of register variables.

2D array syntax is int arr[rows][columns]. So int arr[3][4] creates 3 rows and 4 columns.

Initial: a=1, b=2. After step 1: a=3, b=2. After step 2: a=3, b=1. After step 3: a=2, b=1. Output is '2 1'.

int (*func)(); declares a pointer to a function that returns int. Option A declares a function returning pointer to int.

$\frac{5}{2}$ is integer division (not float division), so result is 2 (integer), then converted to 2.0 (float).