java中的类型转换和最终变量有什么区别？ [英] What is the difference between type casting and final variable in java?

问题描述

我被教过这个：



byte-> short-> int-> long-> float-> double

char-> int-> long-> float-> double



class HelloA {

public static void main（String args []）{

final int a = 5; //更高的数据类型变量

byte b = a; //分配较高数据类型值的较低数据类型变量

变量

System.out.println（b）;

}

}



输出：5



class Hello {

public static void main（String args []）{

final byte b = 65;

char c = b; //这违反了byte-> short-> int

System.out.println（c）;

}

}



输出：A



class Hello {

public static void main（String args []）{

final char c ='A';

byte b = c; //这违反了char-> int

System.out.println（b）;

}

}



输出：65



有人可以详细解释一下吗？



我尝试了什么：



我已经尝试过上述程序。

I have been taught this:

byte->short->int->long->float->double
char->int->long->float->double

class HelloA{
public static void main(String args[]){
final int a=5; //Higher data type variable
byte b=a; //Lower data type variable assigned a value of higher data type
variable
System.out.println(b);
}
}

Output: 5

class Hello{
public static void main(String args[]){
final byte b=65;
char c=b; //This violates byte->short->int
System.out.println(c);
}
}

Output: A

class Hello{
public static void main(String args[]){
final char c='A';
byte b=c; //This violates char->int
System.out.println(b);
}
}

Output: 65

Can someone please explain elaborately?

What I have tried:

I have tried the above programs.

推荐答案

这不是特定于Java，它是计算机存储值的方式，以及程序如何解释它们。



字符 A 是ASCII整理表中的第65个字符。因此，如果将字符变量复制（或引用）到一个字节，编译器会将字节值视为数字，即65.如果将数字65复制到字符变量编译器，则反之亦然将其视为一个字符，在本例中为A. Google用于ASCII整理顺序，您将看到所有字符的数值。

This is not specific to Java, it is how computers store values, and how programs interpret them.

The character A is the 65th character in the ASCII collate table. So if you copy (or reference) a character variable to a byte the compiler treats the byte value as a number, which is 65. And vice versa if you copy the number 65 to a character variable the compiler treats it as a character, which in this case is A. Google for "ASCII collate sequence" and you will see the numeric values of all characters.

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