So You Think You Know C? (2020) [pdf](wordsandbuttons.online)

    sizeof(obj).member

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>

    int main(int argc, char *argv[])
    {
       size_t arglens[argc];
       for (size_t i = 0; i < sizeof arglens / sizeof *arglens; ++i) {
         arglens[i] = strlen(argv[i]);
       }
       printf("Computed %zu lens:\n", sizeof arglens / sizeof *arglens);
       for (size_t i = 0; i < sizeof arglens / sizeof *arglens; ++i) {
         printf("%zu: '%s' is %zu\n", i, argv[i], arglens[i]);
       }
       return 0;
    }

    $ gcc -o arglens -std=c99 arglens.c
    $ ./arglens foo bar baz fooofooofoo
    Computed 5 lens:
    0: './arglens' is 9
    1: 'foo' is 3
    2: 'bar' is 3
    3: 'baz' is 3
    4: 'fooofooofoo' is 11

    int16_t a = 20000;
    int16_t b = a + a;

    unsigned int c = 1;
    signed int d = -2;
    if(c + d > 0)
      puts("1 + -2 > 0");

    void *foo_1 = malloc(1);
    free(foo_1);
    void *foo_2 = malloc(1);
    printf("Checking for same allocatoin: %d", foo_1 == foo_2);

    #include <stdio.h>
    int main(void) {
        puts("Hello World);
    }