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115 lines
2.6 KiB
C++
115 lines
2.6 KiB
C++
#include "Tutorial.h"
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void IndexTutorial() {
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/// .`Index`
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/// `Index` is the the foundation of all U++ associative operations and is one of defining
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/// features of U++.
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/// `Index` is a container very similar to the plain `Vector` (it is random access array of
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/// elements with fast addition at the end) with one additional feature - it is able to fast
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/// retrieve position of element with required value using `Find` method:
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Index<String> ndx;
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ndx.Add("alfa");
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ndx.Add("beta");
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ndx.Add("gamma");
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ndx.Add("delta");
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ndx.Add("kappa");
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DUMP(ndx);
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DUMP(ndx.Find("beta"));
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/// If element is not present in `Index`, `Find` returns a negative value:
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DUMP(ndx.Find("something"));
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/// Any element can be replaced using `Set` method:
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ndx.Set(1, "alfa");
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DUMP(ndx);
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/// If there are more elements with the same value, they can be iterated using `FindNext`
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/// method:
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int fi = ndx.Find("alfa");
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while(fi >= 0) {
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DUMP(fi);
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fi = ndx.FindNext(fi);
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}
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/// `FindAdd` method retrieves position of element like `Find`, but if element is not
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/// present in `Index`, it is added:
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DUMP(ndx.FindAdd("one"));
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DUMP(ndx.FindAdd("two"));
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DUMP(ndx.FindAdd("three"));
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DUMP(ndx.FindAdd("two"));
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DUMP(ndx.FindAdd("three"));
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DUMP(ndx.FindAdd("one"));
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/// Removing elements from random access sequence tends to be expensive, that is why rather
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/// than remove, `Index` supports `Unlink` and `UnlinkKey` operations, which retain the
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/// element in `Index` but make it invisible for `Find` operation:
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ndx.Unlink(2);
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ndx.UnlinkKey("kappa");
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DUMP(ndx.Find(ndx[2]));
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DUMP(ndx.Find("kappa"));
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/// You can test whether element at given position is unlinked using `IsUnlinked` method
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DUMP(ndx.IsUnlinked(1));
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DUMP(ndx.IsUnlinked(2));
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/// Unlinked positions can be reused by `Put` method:
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ndx.Put("foo");
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DUMP(ndx);
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DUMP(ndx.Find("foo"));
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/// You can also remove all unlinked elements from `Index` using `Sweep` method:
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ndx.Sweep();
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DUMP(ndx);
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/// Operations directly removing or inserting elements of Index are expensive, but
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/// available too:
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ndx.Remove(1);
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DUMP(ndx);
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///
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ndx.RemoveKey("two");
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DUMP(ndx);
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///
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ndx.Insert(0, "insert");
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DUMP(ndx);
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/// PickKeys operation allows you to obtain Vector of elements of Index in low
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/// constant time operation (while destroying source Index)
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Vector<String> d = ndx.PickKeys();
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DUMP(d);
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/// Pick-assigning `Vector` to `Index` is supported as well:
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d[0] = "test";
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ndx = pick(d);
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DUMP(ndx);
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///
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}
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