foo.cc: In function 'int main()':
foo.cc:20:14: error: conflicting declaration 'int a [100]'
   20 |  int a,b,m,n,a[100],k;
      |              ^
foo.cc:20:6: note: previous declaration as 'int a'
   20 |  int a,b,m,n,a[100],k;
      |      ^
foo.cc:20:10: warning: unused variable 'm' [-Wunused-variable]
   20 |  int a,b,m,n,a[100],k;
      |          ^
foo.cc:20:12: warning: unused variable 'n' [-Wunused-variable]
   20 |  int a,b,m,n,a[100],k;
      |            ^

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