foo.cc: In function 'int get(char*, int)':
foo.cc:50:9: warning: unused variable 'j' [-Wunused-variable]
   int i,j,k,len=strlen(s);
         ^
foo.cc:50:11: warning: unused variable 'k' [-Wunused-variable]
   int i,j,k,len=strlen(s);
           ^
foo.cc: In function 'int main()':
foo.cc:99:9: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
   gets(a);
         ^
In file included from /usr/include/stdio.h:862:0,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here
 gets (char *__str)
 ^~~~
foo.cc:105:13: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
       gets(b);
             ^
In file included from /usr/include/stdio.h:862:0,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here
 gets (char *__str)
 ^~~~
foo.cc:98:11: warning: unused variable 'k' [-Wunused-variable]
   int i,j,k,n;
           ^
foo.cc:99:7: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
   gets(a);
   ~~~~^~~
foo.cc:102:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d\n",&n);
   ~~~~~^~~~~~~~~~~
foo.cc:105:11: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
       gets(b);
       ~~~~^~~
/tmp/ccw7rgHJ.o: In function `main':
foo.cc:(.text.startup+0x71): warning: the `gets' function is dangerous and should not be used.

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。