foo.cc: In function 'int main()':
foo.cc:8:13: error: conflicting declaration 'int a'
     int n,i,a,b,c,d;
             ^
foo.cc:7:10: note: previous declaration as 'char a [100]'
     char a[100];
          ^
foo.cc:9:13: error: incompatible types in assignment of 'int' to 'char [100]'
     a=b=c=d=0;
             ^
foo.cc:10:11: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     gets(a);
           ^
In file included from /usr/include/stdio.h:862:0,
                 from /usr/include/c++/7/cstdio:42,
                 from /usr/include/c++/7/ext/string_conversions.h:43,
                 from /usr/include/c++/7/bits/basic_string.h:6361,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here
 gets (char *__str)
 ^~~~
foo.cc:16:8: error: lvalue required as increment operand
       a++;
        ^~
foo.cc:10:9: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
     gets(a);
     ~~~~^~~

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