foo.cc: In function ‘int main()’:
foo.cc:5:24: warning: unused variable ‘l’ [-Wunused-variable]
    5 |         int n,a[10000],l,r,num;
      |                        ^
foo.cc:5:26: warning: unused variable ‘r’ [-Wunused-variable]
    5 |         int n,a[10000],l,r,num;
      |                          ^
foo.cc:5:28: warning: unused variable ‘num’ [-Wunused-variable]
    5 |         int n,a[10000],l,r,num;
      |                            ^~~
foo.cc:6:22: warning: ‘n’ is used uninitialized [-Wuninitialized]
    6 |         for(int i=1;i<=n;i++)
      |                     ~^~~
foo.cc:5:13: note: ‘n’ was declared here
    5 |         int n,a[10000],l,r,num;
      |             ^