Possible lossy conversion from double to float, given float values? [duplicate]

Question

if i'm not mistaken, "0.5" are decimal numbers; thus, making it a float value. but why is java telling me that it is a double?. the return statements are detected as errors by java, saying: "incompatible types:possible lossy conversion from double to float"

public float typeDmgMultiplr(String type,String type2){
        if(type.equalsIgnoreCase("grass")){
            if(type2.equalsIgnoreCase("grass"))
                return 0.5;
            else if(type2.equalsIgnoreCase("poison"))
                return 0.5;
            else if(type2.equalsIgnoreCase("fire"))
                return 0.5;
            else
                return 2.0;
        }
        else if(type.equalsIgnoreCase("fire")){
            if(type2.equalsIgnoreCase("grass"))
                return 2.0;
            else if(type2.equalsIgnoreCase("poison"))
                return 1.0;
            else if(type2.equalsIgnoreCase("fire"))
                return 0.5;
            else
                return 0.5;
        }
        else if(type.equalsIgnoreCase("water")){
            if(type2.equalsIgnoreCase("grass"))
                return 0.5;
            else if(type2.equalsIgnoreCase("poison"))
                return 1.0;
            else if(type2.equalsIgnoreCase("fire"))
                return 2.0;
            else
                return 0.5;
        }
        else{
            if(type2.equalsIgnoreCase("grass"))
                return 2.0;
            else if(type2.equalsIgnoreCase("poison"))
                return 0.5;
            else if(type2.equalsIgnoreCase("fire"))
                return 1.0;
            else
                return 1.0;
        }

    }

Answer 1

If I'm not mistaken, 0.5 are decimal numbers; thus, making it a float value.

You should not rely solely on your intuition when learning a new programming language.

In fact, 0.5 is a double literal. For a float literal you need to write 0.5f.

As The Java Language Specification (JLS 3.10.2) states:

A floating-point literal is of type float if it is suffixed with an ASCII letter F or f; otherwise its type is double and it can optionally be suffixed with an ASCII letter D or d.

See also:

• The Oracle Java Tutorial > Primitive Data Types

Answer 2

You have two options.

One is change your method's return type to double.

The other is change the double values you are returning to float values, as many have said in the comments.

public float typeDmgMultiplr(String type,String type2){
    if(type.equalsIgnoreCase("grass")){
        if(type2.equalsIgnoreCase("grass"))
            return 0.5f;
        else if(type2.equalsIgnoreCase("poison"))
            return 0.5f;
        else if(type2.equalsIgnoreCase("fire"))
            return 0.5f;
        else
            return 2.0f;
    }
    else if(type.equalsIgnoreCase("fire")){
        if(type2.equalsIgnoreCase("grass"))
            return 2.0f;
        else if(type2.equalsIgnoreCase("poison"))
            return 1.0f;
        else if(type2.equalsIgnoreCase("fire"))
            return 0.5f;
        else
            return 0.5f;
    }
    else if(type.equalsIgnoreCase("water")){
        if(type2.equalsIgnoreCase("grass"))
            return 0.5f;
        else if(type2.equalsIgnoreCase("poison"))
            return 1.0f;
        else if(type2.equalsIgnoreCase("fire"))
            return 2.0f;
        else
            return 0.5f;
    }
    else{
        if(type2.equalsIgnoreCase("grass"))
            return 2.0f;
        else if(type2.equalsIgnoreCase("poison"))
            return 0.5f;
        else if(type2.equalsIgnoreCase("fire"))
            return 1.0f;
        else
            return 1.0f;
    }

}