foo.cc: In function 'int main()':
foo.cc:13:13: error: conflicting declaration 'int a [10]'
     int a[10] = { 0,0,0,0,0,0,0,0,0,0 };
             ^
foo.cc:10:9: note: previous declaration as 'int a'
     int a, b, p;
         ^
foo.cc:14:13: error: conflicting declaration 'int b [10]'
     int b[10] = { 2,2,2,2,2,2,2,2,2,2 };
             ^
foo.cc:10:12: note: previous declaration as 'int b'
     int a, b, p;
            ^
foo.cc:23:9: warning: unused variable 'sum' [-Wunused-variable]
     int sum = 0;
         ^~~

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