/in/foo.c: In function 'YH':
/in/foo.c:20:4: warning: implicit declaration of function 'printf_s' [-Wimplicit-function-declaration]
    printf_s("%d", yh[i][j]);
    ^~~~~~~~
/in/foo.c: In function 'main':
/in/foo.c:28:2: warning: implicit declaration of function 'scanf_s' [-Wimplicit-function-declaration]
  scanf_s("%d", &n);
  ^~~~~~~
/tmp/cc8LAWgd.o: In function `YH':
foo.c:(.text+0xec): undefined reference to `printf_s'
foo.c:(.text+0x103): undefined reference to `printf_s'
/tmp/cc8LAWgd.o: In function `main':
foo.c:(.text.startup+0x13): undefined reference to `scanf_s'
foo.c:(.text.startup+0x25): undefined reference to `printf_s'
collect2: error: ld returned 1 exit status