C | Structure & Union | Question 4

Consider the following C declaration 

C

struct {
    short s[5];
    union {
         float y;
         long z;
    }u;
} t;

Assume that objects of the type short, float and long occupy 2 bytes, 4 bytes and 8 bytes, respectively. The memory requirement for variable t, ignoring alignment considerations, is (GATE CS 2000)

(A)

22 bytes

(B)

14 bytes

(C)

18 bytes

(D)

10 bytes

Answer: (C)
Explanation:

Short array s[5] will take 10 bytes as size of short is 2 bytes. 

When we declare a union, memory allocated for the union is equal to memory needed for the largest member of it, and all members share this same memory space. Since u is a union, memory allocated to u will be max of float y(4 bytes) and long z(8 bytes). So, total size will be 18 bytes (10 + 8).

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