73 lines
1.6 KiB
C#
73 lines
1.6 KiB
C#
using System;
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interface IContravariant<in T>
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{
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}
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interface ICovariant<out T>
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{
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}
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class D
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{
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public static bool Contra<T> (IContravariant<T> e1, IContravariant<T> e2)
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{
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Console.WriteLine (typeof (T));
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return typeof (T) == typeof (string);
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}
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public static bool Covariant<T> (ICovariant<T> e1, ICovariant<T> e2)
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{
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Console.WriteLine (typeof (T));
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return typeof (T) == typeof (object);
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}
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public static bool CovContCont<T> (ICovariant<T> e1, IContravariant<T> e2, IContravariant<T> e3)
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{
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Console.WriteLine (typeof (T));
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return typeof (T) == typeof (string);
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}
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public static bool ContCovContCov<T> (IContravariant<T> e1, ICovariant<T> e2, IContravariant<T> e3, ICovariant<T> e4)
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{
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Console.WriteLine (typeof (T));
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return typeof (T) == typeof (string);
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}
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public static bool CovCovCont<T> (ICovariant<T> e1, ICovariant<T> e2, IContravariant<T> e3)
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{
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Console.WriteLine (typeof (T));
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return typeof (T) == typeof (string);
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}
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public static int Main ()
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{
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ICovariant<object> a = null;
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ICovariant<string> b = null;
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if (!Covariant (a, b))
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return 1;
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IContravariant<string> a_1 = null;
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IContravariant<object> b_1 = null;
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if (!Contra (a_1, b_1))
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return 2;
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ICovariant<string> a_2 = null;
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IContravariant<object> b_2 = null;
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IContravariant<string> c_2 = null;
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if (!CovContCont (a_2, b_2, c_2))
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return 3;
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IContravariant<object> a_3 = null;
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ICovariant<string> b_3 = null;
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IContravariant<string> c_3 = null;
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ICovariant<string> d_3 = null;
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if (!ContCovContCov (a_3, b_3, c_3, d_3))
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return 4;
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Console.WriteLine ("ok");
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return 0;
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}
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}
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