foo.cc: In function 'int main()':
foo.cc:15:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j, tmp;
            ^
foo.cc:15:15: warning: unused variable 'tmp' [-Wunused-variable]
     int i, j, tmp;
               ^~~
foo.cc:20:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &k);
     ~~~~~^~~~~~~~~~~~~~~~
foo.cc:22:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &arr[0]);
     ~~~~~^~~~~~~~~~~~~~~
foo.cc:27:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &arr[i]);
         ~~~~~^~~~~~~~~~~~~~~

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