C Programming
What will be the value of x after executing: int x = 10; x += 5; x *= 2; ?
Step 1: x = 10. Step 2: x += 5 means x = x + 5 = 15. Step 3: x *= 2 means x = x * 2 = 15 * 2 = 30.
Which of the following correctly defines a structure in C?
A
struct { int a; float b; } MyStruct;
B
structure MyStruct { int a; float b; };
C
struct MyStruct { int a; float b; };
D
class MyStruct { int a; float b; };
Correct Answer:
C. struct MyStruct { int a; float b; };
The correct syntax uses the 'struct' keyword followed by the structure name and then the member declarations enclosed in braces.
What is the purpose of the free() function in C?
A
To allocate memory dynamically
B
To deallocate or release dynamically allocated memory
C
To initialize variables
D
To compare two memory blocks
Correct Answer:
B. To deallocate or release dynamically allocated memory
The free() function deallocates (releases) memory that was previously allocated using malloc(), calloc(), or realloc().
What is the output of: int x = 5; int y = ++x; ?
A
x = 5, y = 5
B
x = 6, y = 6
C
x = 6, y = 5
D
x = 5, y = 6
Correct Answer:
B. x = 6, y = 6
The pre-increment operator ++x increments x first (from 5 to 6), then assigns the new value to y. So x = 6 and y = 6.
What is the correct way to declare a pointer to an integer?
A
int p*;
B
int *p;
C
*int p;
D
pointer int p;
Correct Answer:
B. int *p;
The correct syntax is 'int *p;' where int is the data type, * indicates pointer, and p is the pointer variable name.
What is the output of: int a = 10, b = 20; int *p = &a, *q = &b; printf("%d", *p + *q);?
*p dereferences to a (10) and *q dereferences to b (20). Adding them: 10 + 20 = 30. Pointer arithmetic is used correctly here.
In a struct, how is memory allocated for union members?
A
All members get their own separate memory
B
Members share the same memory location
C
Memory allocated based on member frequency
D
Dynamic allocation only
Correct Answer:
B. Members share the same memory location
In a union, all members share the same memory location. The size of the union equals the size of the largest member. Only one member can hold a value at a time.
What will be the result of: 5 % 2 * 3 / 2?
Modulus, multiplication, and division have equal precedence (left-to-right): (5 % 2) = 1, then (1 * 3) = 3, then (3 / 2) = 1 (integer division). Answer is 1, not 2. Correction: 1 is correct.
What is printed by: char s[] = "hello"; printf("%zu", sizeof(s));?
sizeof(s) includes the null terminator '\0'. "hello" has 5 characters + 1 null terminator = 6 bytes. If s was a pointer, sizeof would give pointer size.
Consider: int *p, q; What is the type of q?
A
Pointer to int
B
Integer
C
Pointer to pointer
D
Character
Correct Answer:
B. Integer
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.
