foo.cc: In function 'int main()':
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&t);
     ~~~~~^~~~~~~~~
foo.cc:14:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&n);
         ~~~~~^~~~~~~~~
foo.cc:17:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ~~~~~^~~~~~~~~~~~