Java += compiler/jre bug?

 

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  • Why don't Java's +=, -=, *=, /= compound assignment operators require casting? 11 answers

    • This is the way += has worked from C . It's "feature" not a bug

    See Java's +=, -=, *=, /= compound assignment operators

    BTW You can try this 

    char ch = '0';
ch *= 1.1; // ch = '4'

    Also see a post of mine http://vanillajava.blogspot.com/2012/11/java-and-implicit-casting.html

    int a = a + (3/2.0); doesn't compile since:

  • int + double leads to a double
  • a is referenced as an int
  • cast from double to int missing

    • int a += 3/2.0; compiles since:

  • int + double leads to a double
  • a is referenced as an int

  • double is castable to an int and luckily, compiler adds an implicit cast similar to:

    int a = (int)(a+ 3/2.0); . This is due to the special op= notation that is interpreted more cleverly from compiler than the basic assignment operator: = .

    • This is not a bug , its a implicit conversion happened.

    for eg. 

    Byte b=3;

b+=5;  //compiles

b=b+5; //doesnt compiles

    Here what happens is 

    a=a+3/2.0;   // 3/2.0 produces double , it add int to double but cant convert it implicitly to int.

a += 3/2.0;  // here implicit conversion after addition of a to 3/2.0 happends from double to int
    链接地址: http://www.djcxy.com/p/73652.html

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