Exam 70-483 topic 2 question 159 discussion

Actual exam question from Microsoft's 70-483

Question #: 159
Topic #: 2

You are developing an application.
The application contains the following code segment (Line numbers are included for reference only):

When you run the code, you receive the following error message: "Cannot implicitly convert type 'object'' to 'int'. An explicit conversion exists (are you missing a cast?)."
You need to ensure that the code can be compiled.
Which code should you use to replace line 05?

A. var2 = ((List<int>)array1) [0];
B. var2 = (int) array1[0];
C. var2 = int.Parse(array1[0]);
D. var2 = array1[0] as int;

Show Suggested Answer

Suggested Answer: B 🗳️

by BitMan20 at Jan. 15, 2020, 11:13 a.m.

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hsjo

Highly Voted 4 years, 7 months ago

answer is b Tested

upvoted 5 times

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Rarabel

Most Recent 4 years, 5 months ago

A.Will not convert System.Collections.ArrayList to System.Collections.Generic.List<T>. B.Correct C. elements of the ArrayList are not strings. D. As operator can be applied only to reference or nullable types.

upvoted 1 times

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josuke

5 years, 1 month ago

Why is D considered invalid? Is it because the conversion would attempt to assign null to var2 if the cast failed? I'm not sure how that would be any worse than throwing an exception in the first place if the standard cast fails.

upvoted 1 times

soats

4 years, 11 months ago

It's because you cannot use AS on non-nullable types

upvoted 3 times

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BitMan20

5 years, 5 months ago

why not c?

upvoted 1 times

osaki

5 years, 5 months ago

cause array1[0] is not a string

upvoted 8 times

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