foo.cc: In function 'int main()':
foo.cc:4:43: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
    4 |     char  a[100],str;int i,b[5]={0};gets(a);
      |                                           ^
In file included from /usr/include/stdio.h:867,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:235:1: note: declared here
  235 | gets (char *__str)
      | ^~~~
foo.cc:4:43: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
    4 |     char  a[100],str;int i,b[5]={0};gets(a);
      |                                           ^
In file included from /usr/include/stdio.h:867,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:235:1: note: declared here
  235 | gets (char *__str)
      | ^~~~
foo.cc:4:41: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
    4 |     char  a[100],str;int i,b[5]={0};gets(a);
      |                                     ~~~~^~~
/usr/bin/ld: /tmp/ccW8EOnf.o: in function `main':
foo.cc:(.text.startup+0x27): warning: the `gets' function is dangerous and should not be used.

[Hydro](https://hydro.ac)提供评测服务