C# and .NET interview questions on Coalescing operator.
- By Shiv Prasad Koirala in C#
- Dec 16th, 2013
- 7875
- 0
When should we use "??" (NULL Coalescing operator) ?
"??" is a NULL coalescing operator. If you see the English meaning of coalescing it says "consolidate together". Coalescing operator returns the first NON-NULL value from a chain. For example below is a simple coalescing code which chains four strings.
So if "str1" is null it will try "str2" , if "str2" is null it will try "str3" and so on until it finds a string with a non-null value.
string final =str1 ?? str2 ?? str3 ?? str4;
What is the benefit of coalescing?
You do not need to write long if condition as shown below.
if (str1 != null)
final = str1;
}
else
if (str2 != null)
final = str2;
}
else
if (str3 != null)
final = str3;
}
else
if (str4 != null)
final = str4;
}
}
}
}
This is a nice tutorial created by Questpond on Coalescing operator in c#.
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Shiv Prasad Koirala
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