foo.cc: In function 'int main()':
foo.cc:17:6: warning: statement has no effect [-Wunused-value]
 for(i;i<n;i++)
      ^
foo.cc:10:41: warning: variable 'num' set but not used [-Wunused-but-set-variable]
 int t,i=0,k,j,n,n1,n2,max,min,last,min2,num;
                                         ^~~
foo.cc:12:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&t);
 ~~~~~^~~~~~~~~
foo.cc:16:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&n);
 ~~~~~^~~~~~~~~
foo.cc:19:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&a[i]);
 ~~~~~^~~~~~~~~~~~

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