关于Java的基础变量隐式转换 - 黑马程序员技术交流社区

/*
基础类型的隐式转换：
byte,short,char --> int --> long --> float --> double
byte可隐转short
除了boolean,基础类型之间都可进行强制转换
*/
public class TypeDemo {
public static void isType(byte b) {System.out.println("it is a byte");} //注释该行，isType(b)输出short
public static void isType(short s) {System.out.println("it is a short");} //注释该行，isType(s)输出int
public static void isType(char c) {System.out.println("it is a char");} //注释该行，isType(c)输出int
public static void isType(int i) {System.out.println("it is a int");} //注释该行，上四个输出long
public static void isType(long l) {System.out.println("it is a long");} //注释该行，上五输出float
public static void isType(float f) {System.out.println("it is a float");} //注释该行，全输出double
public static void isType(double d) {System.out.println("it is a double");}
public static void main(String[] args) {
byte b = 1;
short s = 1;
short s2 = b; //byte可隐转为short
char c = 'c';
//char c2 = b; //报错，byte无法隐转char
int i = 1;
long l = 1;
/*
整数型和char总结
byte,short,char 中，只有byte可隐转为short
byte,short,char 都可隐转int、float,运算时都隐转为int,'整数常量'默认类型为int
赋值优化机制，'整数常量'可强转为 short,byte,char 赋值给基础数据类型
*/
//float f = 1.1; 可用float f = 1; 1隐转float，但是不能赋值默认double型小数给float
float f = 1.0F;
float f2 = 1L; //可把long类型隐式转换为float
double d = 1.0D;
/*
isType(c+b); //it is a int
isType(s+b); //it is a int ,char,short,byte 整数型和char型运算时会隐转为int
isType(f+l); //it is a double, 浮点数运算会隐转为double
*/
isType(b);
isType(s);
isType(c);
isType(i);
isType(l);
isType(f);
isType(d);
}
}

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