foo.cc: In function 'int main()':
foo.cc:10:2: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(c);
  ^~~~
In file included from foo.cc:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
foo.cc:10:8: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(c);
        ^
In file included from foo.cc:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
foo.cc:26:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(k=2;k<n;k++)
  ^~~
foo.cc:29:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   if(k == n)//是质数
   ^~
/tmp/ccDvqPHT.o: In function `main':
foo.cc:(.text.startup+0xc): warning: the `gets' function is dangerous and should not be used.

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-23T06:43:49.230Z","handle":"2020-02-23T06:43:49.230Z","done":"2020-02-23T06:43:49.997Z"}