foo.cc: In function 'int main()':
foo.cc:6:10: warning: unused variable 'm' [-Wunused-variable]
    6 |  int n,k,m;
      |          ^
foo.cc:10:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |   scanf("%d",&a[i]);
      |   ~~~~~^~~~~~~~~~~~

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