当我尝试调用在主方法中创建的方法时，出现错误

Question

public class MyClass
{
    public  static short subtractNumbers (short a, byte b, float k )
    {
        int x=(short)a;
        int y=(short)b;
        int z=(short)k;
        return (short)(x+y-z);
    }
    public static void main (String[] args)
    {
        System.out.println(subtractNumbers(127,127,0.0f));
    }    
}

When I compile and run the program, I am getting errors, as:

error: method subtractNumbers in class MyClass cannot be applied to given types;

System.out.println(subtractNumbers(127,127,0.0f));

required: short,byte,float

found: int,int,float

reason: actual argument int cannot be converted to short by method invocation conversion

Why are the code causing the errors? I am wondering.

Thanks in advance for the help it would be appreciated.

Answer 1

As the error states you are passing 2 int numbers instead of a short and a byte. Try:

System.out.println(subtractNumbers((short) 127, (byte) 127, 0.0f));

Or change your method to:

public static short subtractNumbers(int a, int b, float k) {
    return (short) (a + b - (int) k);
}

Answer 2

The reason for the error is that in Java an integer literal is an int unless:

1. you specify it as a long eg 128L (There is no specifier for short or byte unfortunately)
2. assign it to another integer type eg short s = 1;
3. you cast it explicitly eg (short) 4
4. you have a Widening primitive conversion eg pass an int to a method expecting a long

A conversion from int to short or byte is called a Narrowing primitive conversion and it may fail generally, if the int is too large to fit in a short .

Documentation

Answer 3

Try creating variables before calling the subtractNumbers method. That way, you can set the type you want and it won't complain about the types not being the same.