C Programming - MCQ Practice Questions

The C standard guarantees int is at least 2 bytes, but most 32-bit systems use 4 bytes. The exact size is implementation-dependent.

The declaration uses comma separation. 'int arr[10]' declares an array of 10 integers, while '*ptr' declares a pointer to int.

Both 'const int' and 'int const' are valid and equivalent ways to declare a constant integer in C.

C allows implicit type conversion. When assigning larger to smaller type, truncation or data loss may occur without any compiler error.

# Understanding `sizeof()` Operator in C

The `sizeof()` operator returns the size of data types in bytes, which varies depending on the compiler and system architecture.

Step 1: Analyze sizeof(int)

In C, the size of `int` is implementation-defined and depends on the system architecture and compiler.

Step 2: Analyze sizeof(char) and Calculate Total

The `char` data type always occupies exactly 1 byte across all standard C implementations, but `int` varies by platform.

For a 16-bit system: $2+1=3$ bytes

For a 32-bit system: $4+1=5$ bytes

For a 64-bit system: $4+1=5$ bytes (typically)

The output depends on the system's architecture. The minimum guaranteed value is 3 bytes (on 16-bit systems), but it can be higher on modern systems.

Correct Answer: (C) Depends on system (at least 3)

char (signed) has range -128 to 127, while unsigned char has 0 to 255. The latter can represent extended ASCII characters (128-255).

When assigning a double to int, C performs implicit type conversion with truncation (not rounding). The decimal part is discarded.

Uninitialized local variables contain garbage values (random data from memory). Static/global variables are initialized to 0 by default.

%ld is for long int, %lld is for long long int, and %d is for regular int. Using wrong specifier can cause undefined behavior.

Static variables retain their values between function calls and are initialized only once, maintaining state across invocations.

*p dereferences pointer to get value 10, then 10+5=15 is printed.

Both 'int x;' and 'static int x;' allocate memory. Extern only declares without allocation.

Size of long double varies: typically 12 or 16 bytes on different systems and compilers.

Global variables with extern keyword have global scope and external linkage across translation units.

Volatile prevents compiler optimizations by signaling the variable may change outside program control (hardware/signals).

Local variables declared inside functions have automatic storage duration and are destroyed on function exit.

(int)(3.9) = 3, then 3 + 0.5 = 3.5, but %d prints as int 3 (truncated).

In C99+, auto is rarely used since local variables are automatic by default, but it remains valid syntax.

When -10 is assigned to an unsigned int format (%u), it gets interpreted as a large positive number due to two's complement representation on a 32-bit system.

The 'static' keyword gives a variable static storage duration, preserving its value between function calls.