What happens if 'free(ptr)' is called twice on the same dynamically allocated pointer without reinitialization?
Freeing an already freed memory address causes double-free undefined behavior or heap corruption.
In C, how are multi-dimensional arrays stored in memory?
C stores multi-dimensional arrays in contiguous row-major order (row elements are stored sequentially).
What is the value of 'a[1][1]' for 'int a[2][2] = {{1, 2}, {3, 4}};'?
Index [1][1] accesses row index 1, column index 1, which contains element 4.
What is the result of '1 << 3' in decimal?
Left shift 1 by 3 bits computes 1 * $2^3$ = 8.
What will be the output of 'printf("%d", 7 ^ 7);'?
Bitwise XOR of any integer with itself yields 0.