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C# C# Objects Encapsulation and Arrays Arrays

Did you declare the 'lapTimes' variable as a 'double[]' or 'var'? Um...What?

The first task of this Code Challenge asked me to declare an array of doubles named lapTimes with a length of 4. But then I got a 'Bummer!', asking whether I declared the array with 'double' or 'var'. But I declared it with 'double', which is what I thought they wanted. So I then tried replacing 'double' with 'var', but the same 'Bummer!' message popped up. What am I doing wrong here?

double []lapTimes = new[4]

2 Answers

28,558 Points

There are three issues:

  1. The task is a bit picky about how your code is formatted. It wants the square brackets [] to be placed right after the word double without any spaces between them. Either way is technically valid in C# but you have to go with that the challenge is expecting if you want your code to pass.

  2. You have to include the word double after the word new in your code. This is not just a quirk of the challenge checker but an actual C# requirement. Your code would not compile without specifying what type of object you are creating with the new keyword.

  3. You are not terminating the line with a semicolon.

If you fix those three issues like this

double[] lapTimes = new double[4];

Then your code will work.

It worked! Thanks for the help. But it was mentioned in the video that preceded this challenge that double wasn't always needed to be put after the word new. They said that the computer would be able to identify what type of object was in the array just by seeing what the array contained. Was the task just pick, or did I misunderstand something? Regardless, the code worked, so thanks again.

28,558 Points

That is true, but in order to identify the type based on what is in the array, there actually needs to be something in the array.

In other words when you declare an array and specify some items at the same time like this:

double[] lapTimes = new[] {2.4, 3.1, 1.4};

Then it is fine to not specify the type and size of the array. But when the array is empty, which the array you make in this task is. Then you have to tell C# what type the array contains, since there is no content to base it on. That is what I meant to convey in my original post.

Keenan Johnson
Keenan Johnson
13,841 Points

When declaring an array, the syntax you want is datatype[]. Also, when defining the array length, the syntax you want is datatype[length].


double[] lapTimes = new double[20];