foo.cc: In function 'int main()':
foo.cc:6:14: warning: unused variable 'k' [-Wunused-variable]
    6 |    int i , j,k,sum=0,cnt,s;
      |              ^
foo.cc:11:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |    scanf("%d",&a[i]);
      |    ~~~~~^~~~~~~~~~~~

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