yield break in c#

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What does “yield break;” do in C#? 9 answers

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Talking about C# , If you want to write an iterator that returns nothing if the source is null or empty. Here is an example:

public IEnumerable<T> EnumerateThroughNull<T>(IEnumerable<T> source)
{
    if (source == null)
        yield break;

    foreach (T item in source)
        yield return item;
}

It becomes impossible to return an empty set inside an iterator without the yield break . Also it specifies that an iterator has come to an end. You can think of yield break as return statement which does not return value.

int i = 0;
while (true) 
{
    if (i < 5)       
        yield return i;
    else            
        yield break; // note that i++ will not be executed after this statement
    i++;
}    

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