/in/foo.c: In function 'main':
/in/foo.c:27:5: warning: implicit declaration of function 'gets' [-Wimplicit-function-declaration]
     gets(s);
     ^~~~
/in/foo.c:28:5: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
     printf("%d\n",kmp(s));
     ^~~~~~
/in/foo.c:28:5: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:28:5: note: include '<stdio.h>' or provide a declaration of 'printf'
/tmp/ccjqzg31.o: In function `main':
foo.c:(.text.startup+0xe): warning: the `gets' function is dangerous and should not be used.