AP102 2016/6/27 JAVA 第一堂

public class MainClass
{
    public static void main(String[] argv)
    {
        byte    b = 1;
        short   s = 2;
        int     i = 3;
        long    l = 4;

        float   f = 1.1f;
        double  d = 1.2;

        boolean bool = true;

        char    c = 'a';

        String text = "hello world";
        System.out.println("b = " + b + "\ns = " + s);

    }
}

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強制轉型

class Casting{
    public static void main(String[] args){
        int i = 1;
        double d = 11.1;
        double sum1 = i + d;
        int sum2 = (int)(i + d);
        System.out.println(sum1);
        System.out.println(sum2);
    }
}

---

數字與字串串接

class ConcatenateOP{
    public static void main(String[] args){
        String str1 = "123";
        String str2 = str1 + 10;
        int i = 123;
        double d = 3.12;
        System.out.println(str2);
        System.out.println(i + d); 
        System.out.println(i + " " + d);
        System.out.println("i = " + i + ", d = " + d);
    }
}

結果

12310
126.12
123 3.12
i = 123, d = 3.12