Java中变量的自动类型转换与强制类型转换

Java中变量的自动类型转换与强制类型转换

/*
变量的自动类型转换与强制类型转换
自动类型转换-数据类型按容量大小排序为：char,byte
*/
class TestVariable1{
    public static void main(String[] args){
        short s1 = 1;
        int i1 = 2;
        int i2 = s1 + i1;
        float f1 = 12.2f;
        float f2= f1 + i1;
        //float f3 = f1 + 12.22;
        //TestVariable1.java:14: 错误: 不兼容的类型: 从double转换到float可能会有损失
        char c1 = 'a';
        //a = 97
        c1 = 'A';
        //A = 65
        int i3 = c1 + s1;
        System.out.println(f2);
        //System.out.println(f3);
        System.out.println(i3);
        short ss1 = 12;
        byte bb1 = 1;
        char cc1 = 'a';
        int ii1 = ss1 + bb1;
        System.out.println(ii1);
        int ii2 = cc1 + bb1;
        System.out.println(ii2);
        //强制类型转换
        long l1 = 12345L;
        int m1 = (int)l1;
        System.out.println(m1);
        byte by1 = (byte)m1;
        System.out.println(by1);
        //平时常用的字符串，也是一种数据类型
        String nation = "中国人";
        System.out.println(nation);
//当把任何基本类型的值和字符串值进行连接运算时(+)，基本类型的值将自动转化为字符串类型。
        String st1 = "hello";
        String str1 = st1 + m1;
        System.out.println(str1);
        //举例
        String str2 = "hello";
        int myInt1 = 12;
        char cha1 = 'a';
        System.out.println(str2+myInt1+cha1);//hello12a
        System.out.println(myInt1+cha1);//12+97=109
        System.out.println(myInt1+cha1+myInt1);//12+97+12=121
        System.out.println(cha1+str2+myInt1);//ahello12
        System.out.println(myInt1);//12
        System.out.println(cha1);//a
    }

}