如何在printf中換行？

如何在printf中換行
    // C2001b.cpp
    printf("Hello,\n\
    world\n");
    printf("Hello,\
    \nworld\n");
    printf("Hello,\n"
    "world\n");
    printf("Hello,"
    "\nworld\n");
    printf("Hello,"
    " world\n");
    printf("Hello,\
    world\n");