/in/foo.c: In function 'main':
/in/foo.c:9:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
gets(a);
^~~~
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:8:17: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
int i,len,flag,b,s1=0,s2=0;
^
/tmp/ccZu3zSw.o: In function `main':
foo.c:(.text.startup+0x1d): warning: the `gets' function is dangerous and should not be used.