/in/foo.c: In function 'main':
/in/foo.c:9:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(str);
  ^~~~
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:21:26: error: lvalue required as left operand of assignment
     str[i]=str[i]-'Z'+'A'=1;
                          ^