问题
When i convert:
int B=1;
boolean A=B;
It gives error: Incompatible types, which is true
But when I write this code:
int C=0;
boolean A=C==1;
it gives false while if I change value of C to 1 it gives true. I don't understand how compiler is doing it.
回答1:
int C=0;
boolean A=C==1;
The compiler first gives C a zero.
Variable : C
Value : 0
Now The Assignment statement,
We know that the assignment statement evaluates the right part first and the gives it to the left.
The right part ==> C == 1
Here, This is an expression which evaluates to true or false. In this case it is false as c is 0.
So the R.H.S is false.
Now this gets assigned to the L.H.S which is A.
A = ( C == 1 ) ==> A = false
As A is a boolean this is a right statement
回答2:
C==1 is an expression whose result is boolean (it's the comparison operator). It returns true if C equals to 1 and false otherwise.
Therefore boolean A=C==1; is a valid assignment of a boolean value to a boolean variable.
回答3:
It checks c==1 first and result getting assigned to A.
as C is not 1 so expression value is resulting to false which is assigned to A
来源：https://stackoverflow.com/questions/31308896/how-java-converts-int-to-boolean