foo.cc: In function 'int main()':
foo.cc:10:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 | scanf("%d",&a);
      | ~~~~~^~~~~~~~~
foo.cc:9:9: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
    9 | int a,i,j,max;
      |         ^

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