foo.cc: In function 'int main()':
foo.cc:5:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    5 |  scanf("%d",&t);
      |  ~~~~~^~~~~~~~~
foo.cc:7:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 |   scanf("%d",&n);
      |   ~~~~~^~~~~~~~~
foo.cc:9:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |    scanf("%d",&a[j]);
      |    ~~~~~^~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务