#1,199 – Equality and Inequality with Nullable Types

The equality and inequality operators work with nullable types as follows:

  • If both operands are non-null, the operators are applied to the values
  • If one operand is null and the other has a value, == returns false, != returns true
  • If both operands are null, == returns true and != returns false
            int? val1 = 5;
            int? val2 = 10;
            int? val3 = null;
            int? val4 = null;
            int? val5 = 10;

            bool b1 = val1 == val2;   // False
            b1 = val2 == val5;        // True
            b1 = val1 == val3;        // False
            b1 = val1 != val3;        // True
            b1 = val3 == val4;        // True
            b1 = val3 != val4;        // False
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About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

2 Responses to #1,199 – Equality and Inequality with Nullable Types

  1. Pingback: Dew Drop – October 8, 2014 (#1872) | Morning Dew

  2. David says:

    Note that this is different from SQL, where NULL != NULL.

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