各数据类型之间的关系

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当表达式中有类型不匹配时，有下列处理方法：

1.占用较少字节的数据类型会转换成占用较多字节的数据类型。

2.有short和int类型时，则用int类型。

3.字符类型会转换成int类型。

4.int类型转换成float类型。

5.若一个操作数的类型为string，则其他的操作数也会转换成string类型。

6.布尔类型不能转换至其他类型。

程序的3种基本结构的作用：http://zhidao.baidu.com/question/561343838.html

package com.huawei.test;

public class Test1
{
    public static void main(String[] args)
    {
        char cc = '无';
        char c= 0;//（字符）
        char c1= 1;//（字符）
        char c2 = 80;//（ASCII美国字符标准码）A

/*******************************************************/
//        c = c+cc; cannot convert from int to char

        Short ss = '死';//（ASCII美国字符标准码）1= 49 0=48
        Short s = 1;//（ASCII美国字符标准码）1= 49 0=48
        Short s1 = 1000; //short 16 2 最大32767

/*******************************************************/
//        s= c+s;cannot convert from int to Short

        long LL = '死';//（ASCII美国字符标准码）a=97
        Long L = 1l;//（ASCII美国字符标准码）a=97
        Long L1 = 100000l;//(自动为int最大值就是这个,10位)
        Long L2 = 9223372036854775807L; //最大19位 9223372036854775807 (大些开头，就局限L结尾)

/*******************************************************/
        L = L+s;
        L = L+c;

        Byte bb= 'a';
        byte b= 1;
        byte b1 = 100; //最大127

/*******************************************************/
//        c =c2+b1; cannot convert from int to char

        float ff = '无';
        float f = 1f;
        float f1 =   100000;//(自动为int最大值就是这个,10位);
        float f2 = 340000000000000000000000099900000000009f; //最大38位

/*******************************************************/
        int i = c+s;
        i= c+b;
        i=ss+bb+cc;

        double dd = '无'; //最大38位
        double d = 1; //最大38位
        double d1 = 2222; //最大38位
        double d2 = 22222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222.0; //最大38位
        String str = String.valueOf(d2);
/*******************************************************/
        d = d +c;
        d = b+c;
        d= i+c;
        d= s+c;
        d= s+b+c+L+d;

//      s = d+c;Type mismatch: cannot convert from double to Short
//      s = b+c;pe mismatch: cannot convert from int to Short
//      L= b+c;Type mismatch: cannot convert from int to Long
//      L = f+c;Type mismatch: cannot convert from float to Long
        L = b+c+L;
        L = i +L;
        f = b+c;
        f= s+c;
        f = i+c;
        f=f+c;
//      f = d+c;Type mismatch: cannot convert from double to float
//      s=b;Type mismatch: cannot convert from byte to Short
//      s= c;Type mismatch: cannot convert from char to Short
//      i = f+c;Type mismatch: cannot convert from float to int
//      i =d+c;Type mismatch: cannot convert from double to int
//      c = s+b;Type mismatch: cannot convert from int to char
//      c= s;Type mismatch: cannot convert from Short to char
//      c=b;Type mismatch: cannot convert from byte to char
//      b=c;Type mismatch: cannot convert from char to byte
//      str = s+c+d+b+L+d;Type mismatch: cannot convert from double to String
//      L =str;Type mismatch: cannot convert from String to Long
//      str = L;Type mismatch: cannot convert from Long to String


        System.out.println(" |cc| "+cc+" |c| "+c+" |c1| "+c1+" |c2| "+c2+"----"+(cc+ss)+"--"+(c1+c2)+"--"+(c2+cc));
        System.out.println(" |ss| "+ss+" |s| "+s+" |s1| "+s1+"-----"+(s+s1));
        System.out.println(" |LL| "+LL+" |L| "+L+" |L1| "+L1+" |L2| "+L2+"----"+(L+L1));
        System.out.println(" |bb| "+bb+" |b| "+b+" |b1| "+b1 +"---" +(b+b1));
        System.out.println(" |ff| "+ff+" |f| "+f+" |f1| "+f1 +" |f2| "+f2 +"----"+(f+f1));
        System.out.println(" |dd| "+dd+" |d| "+d+" |d1| "+d1 +" |d2| "+d2+" |ss.length()| "+str.length()+"---"+(d1+d2)+"------"+(d+d1));
    }
}

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