/in/foo.c: In function 'main':
/in/foo.c:5:5: warning: implicit declaration of function 'gets' [-Wimplicit-function-declaration]
     gets(x);
     ^~~~
/in/foo.c:19:5: warning: implicit declaration of function 'puts' [-Wimplicit-function-declaration]
     puts(a);
     ^~~~
/tmp/cc1xh0ih.o: In function `main':
foo.c:(.text.startup+0x13): warning: the `gets' function is dangerous and should not be used.