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C# C# Objects Loops and Final Touches For Loops

Posted by Claire Gersabeck
Claire Gersabeck
2,368 Points

Won't let me use += operator for a double

I am getting an error that tells me that I cannot use the += operator, so I tried to write it as sum = sum + frogs[i]; and it still is giving me an error.

FrogStats.cs 
namespace Treehouse.CodeChallenges
{
    class FrogStats
    {
        public static double GetAverageTongueLength(Frog[] frogs)
        {
            double sum = 0.0;
            for(int i=0; i<frogs.Length; i++){
                 sum = sum + frogs[i];
            }
            double avg = sum / frogs.Length;
            return avg;
        }
    }
}
Frog.cs 
namespace Treehouse.CodeChallenges
{
    public class Frog
    {
        public int TongueLength { get; }

        public Frog(int tongueLength)
        {
            TongueLength = tongueLength;
        }
    }
}

1 Answer

Dane Parchment
MOD
Dane Parchment
Treehouse Moderator 11,075 Points
Dane Parchment
Dane Parchment
Treehouse Moderator 11,075 Points

It is not that you can't use the += operator with doubles. It is because of what you are trying to add to the double. Think carefully about your code, you are trying to add a frog object to a double. Basically you are trying to add a frog to a number, those are not compatible types to be trying to add together. It would be like trying to say: what does 1.2 + a cat equal?

So instead a hint on how to solve this would be getting each of the frog's tongue lengths, adding them together and then dividing by the total number of frogs.

Claire Gersabeck
Claire Gersabeck
2,368 Points

Thank you! That helps A LOT!