Consider the following C structure on a typical 32-bit system, where int is 4 bytes, char is 1 byte, and the compiler applies default structure padding for member alignment: struct Example {     char a;     int b;     char c; }; printf("%d", sizeof(struct Example));

Due to structure padding for memory alignment, the compiler inserts extra bytes so each member sits at its properly aligned offset, and the total structure size becomes a multiple of the largest member's alignment requirement. Here: char a occupies 1 byte, followed by 3 padding bytes so that int b begins at a 4-byte-aligned offset; int b then occupies 4 bytes; char c occupies 1 byte, followed by 3 trailing padding bytes so the overall structure size is a multiple of 4 (int's alignment). Total size = 1 + 3 + 4 + 1 + 3 = 12 bytes, even though the actual useful data totals only 6 bytes.