/in/foo.c: In function 'main':
/in/foo.c:42:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for (int i = 0; i < n3; i++) 
     ^~~
/in/foo.c:44:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  n4 = UnionSet(a1,n1, a2,n2, a4);
  ^~