We are using the last version of c#. We need the complete table of Operators priority, but we can't find it.
For example, what's the priority here?
string c = a ?? string.Empty "example";
where a is a string.
CodePudding user response：
(Credit for the link goes to Bill Tür, who answered in a comment.)
For example, what's the priority here?
The search term you are looking for is operator precedence.
The operator precedence is documented in the C# language reference, currently found at:
Regarding your concrete example, appears earlier in the list than ?? and, thus, has a higher precedence. This means that
a ?? b c
is evaluated as
a ?? (b c)
Note to address a common misconception: Operator precedence does not affect the order of evaluation: a is still evaluated before both b and c. Operands in C# are always evaluated left-to-right.
CodePudding user response：
The ?? operator is called the null-coalescing operator. It returns the left-hand operand if the operand is not null; otherwise it returns the right hand operand.
So, in your case, a will be checked if it's null or not. in case a is null, c will be assigned with the string "example". if a is not a null, c will be assigned with the a string value.
If you're used to ternary operators, you can translate:
string c = a ?? string.Empty "example";
to:
string c = a != null ? a : string.Empty "example";