编译时非法启动类型错误

Question

Am writing a program which allows two superheros to fight. However when I try to compile the I get an illegal start type error.

public class Fight {

    public static void main(String [] args); {
        Superhero Spiderman = new Superhero();
        Superhero TheHumanTorch = new Superhero(21);
    }

    public Spiderman fight(TheHumanTorch opponet); {
        System.out.Println(TheHumanTorch);
    }

    private void powerUp(100); {
        Spiderman Strength = Srength + 100;
    }

    public Spiderman fight(TheHumanTorch opponet); {
        System.out.Println(Spiderman);
    }
}

---

public class Superhero {

    public String Name;
    private int Strength;

    public Superhero(String n, int s) {

        Name = n;
        Strength = s;

    }

    public Superhero(String n) {

        Name = n;
        Strength = 10;
    }

    private void powerUp(int powerUp) {
        Srength = Srength + powerUp;
    }

}

    public Superhero fight(Superhero opponet) {
        if (this.Strength > opponet.Strength) {
            return this;
        } else {
            return opponet;
        }
    }

    public String toString() {
        if (this.Stength) {
            return "Superhero";
        } else {
            return "Superhero opponet";
        }
    }
}

Answer 1

It is being caused by this code:

private void powerUp(100); {
    Spiderman Strength = Srength + 100;
}

You need to provide the type and parameter name to the method. I'm guessing you meant to provide something like amount to it. Something like this could compile if a class named Spiderman was available and Srength was available to the scope of this method:

private void powerUp(int amount) {
    Spiderman Strength = Srength + amount;
}

Another issue is that you have too many brackets in your class definition:

    private void powerUp(int powerUp) {
        Srength = Srength + powerUp;
    }

}
// This is the closing bracket for the class definition.

You should remove that extra bracket. Your code below is not being included in the class definition.

There are plenty of other issues, as well. When you try to compile, the compiler will help you discover these problems and give you context as to how to fix them.

You seem like you may be new to programming, so you may just be using an editor like Notepad or VI. A lot of developers (most) use a tool called an IDE , which makes a developer's life much better. A few examples would be:

• IntelliJ IDEA
• Eclipse
• Netbeans

As Andreas mentioned, your main and other methods have semicolons when they should not:

public static void main(String [] args); {

Should be:

public static void main(String [] args) {

There are plenty of other issues that your compiler (or IDE) will catch that you will need to address, too. Here are a just a few examples your compiler will find, that you will have to figure out how to fix:

• Spiderman isn't a defined class
• TheHumanTorch isn't a defined class
• Println isn't a method defined on java.io.PrintStream (your System.out.Println call)
• Srength and Stength will not be resolved. You probably mean Strength

I recommend that you slowly iterate over your code with a Java resource nearby to help guide you through some examples and compare what you wrote vs. how the examples are written.