foo.cc: In function 'int main()':
foo.cc:21:37: warning: 'x' may be used uninitialized [-Wmaybe-uninitialized]
   21 |                                 a[j]=x;
      |                                 ~~~~^~
foo.cc:18:37: note: 'x' was declared here
   18 |                                 int x;
      |                                     ^

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