/in/foo.cc: In function 'int main()':
/in/foo.cc:14:9: warning: unused variable 'a' [-Wunused-variable]
 int i,k,a,result,n;
         ^
/in/foo.cc:16:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&n);
               ^
/in/foo.cc:17:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 for(i=0;i<n;i++)scanf("%d",&num[i]);
                                    ^