size

    struct st1{
        char a;
        char* a1;
        char* a2;
    };

    struct st2 {
        char* name;
        struct st1 stt1;
    };

    struct st2* sttA;
    struct st2 sttB;

    printf("sizeof int: %zu\n", sizeof(int));
    printf("sizeof char*: %zu\n", sizeof(char*));
    printf("%zu\n", sizeof (struct st1));
    printf("%zu\n\n", sizeof (struct st2));

    printf("%zu\n", sizeof *sttA);
    printf("%zu\n", sizeof sttB);
    printf("%zu\n", sizeof sttB.stt1);

sizeof int: 4
sizeof char*: 8
24
32

32
32
24

    struct st1{
        int a;
        char* a1;
        char* a2;
    };

    struct st2 {
        char* name;
        struct st1 stt1;
    };

    struct st2* sttA;
    struct st2 sttB;

    printf("sizeof int: %zu\n", sizeof(int));
    printf("sizeof char*: %zu\n", sizeof(char*));
    printf("%zu\n", sizeof (struct st1));
    printf("%zu\n\n", sizeof (struct st2));

    printf("%zu\n", sizeof *sttA);
    printf("%zu\n", sizeof sttB);
    printf("%zu\n", sizeof sttB.stt1);

sizeof int: 4
sizeof char*: 8
24
32

32
32
24