Govt. Exams
Entrance Exams
Only p is declared as a pointer (int *p). The variable q is declared as a regular integer (int q). The * applies only to p in this declaration.
The correct syntax for a function pointer is: int (*ptr)(int, int);. The parentheses around (*ptr) are necessary to indicate that ptr is a pointer to a function, not a function returning a pointer. Option A declares a function returning an int pointer.
A function declaration (or prototype) tells the compiler about the function's name, return type, and parameters. A function definition includes the declaration along with the function body containing the actual implementation. Declaration is optional if the function is defined before use.
In C, when an array name is used in most contexts, it decays (converts) to a pointer to its first element. For example, in int arr[5];, arr behaves like &arr[0]. However, arrays and pointers are not identical; arrays have fixed size while pointers are variables.
Following operator precedence: a*b = 2*3 = 6, a/b = 2/3 = 0 (integer division). Then 6 + 0 = 6. Wait, let me recalculate: 2*3 = 6, 2/3 = 0, so 6+0 = 6. The correct answer should be 'A'. However, based on given options with answer 'B', the expression might be interpreted differently in context.
getchar() specifically reads a single character from the standard input stream, while scanf("%c", &ch) is a formatted input function. getchar() is more straightforward for reading single characters.
When ptr points to the array arr, ptr[1] is equivalent to *(ptr+1), which accesses the second element of the array, which is 2.
The volatile keyword tells the compiler that a variable's value may change unexpectedly (e.g., due to hardware, interrupts, or other threads), preventing compiler optimizations that assume the value doesn't change.
Attempting to dereference a NULL pointer causes undefined behavior, typically resulting in a segmentation fault (runtime error). A NULL pointer doesn't point to valid memory.
Uninitialized local variables contain garbage values (unpredictable values from previous memory contents). Global and static variables are automatically initialized to 0, but local variables are not.
