/in/foo.c: In function 'main':
/in/foo.c:7:5: warning: 'gets' is deprecated [-Wdeprecated-declarations]
     gets(s1);
     ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:8:5: warning: 'gets' is deprecated [-Wdeprecated-declarations]
     gets(s2);
     ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:9:5: warning: 'gets' is deprecated [-Wdeprecated-declarations]
     gets(s3);
     ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:6:15: warning: variable 'm3' set but not used [-Wunused-but-set-variable]
     int m1,m2,m3,i,k,j,r;
               ^~
/tmp/ccQx2jjF.o: In function `main':
foo.c:(.text.startup+0x25): warning: the `gets' function is dangerous and should not be used.