变量没有声明的错误

1.分析错误原因

    public class Test {
        public static void main(String[] args) {
            int a = 3;
            int b = 4;
            int c = 20;

            average = (a + b + c)/5.0;
            System.out.println(average);
        }
    }

变量average没有声明