在Java中将负整数类型转换为long类型时会发生什么？

Question

int i = 0;

long ll = 0L;

i = -1 - 2; //  -3

i = (int) -1 - 2; // -3

ll = (long) - (int) -1 - 2;// -1

i = (int) +(long) -(int) -1 - 2;//-1

ll = (long) +(int) -1 - 2; // -3

In the above program at the line

 ll = (long) - (int) -1-2;  

ll value is -1 . How does its value becomes -1 just by type casting? Shouldn't it be like 3 or -3?

Answer 1

i = (int) +(long) -(int) -1 - 2;

unary operator will be evaluated first then binary because of unary operator is higher precedence than binary operator.

so -(int) -1 will be evaluated first and it will become +1

then +(long)+1 will be +1

and after that (int)+1 will be evaluated so it will become +1

then +1-2 will be evaluated as -1 so you are getting -1 . same operation will be performed for other statements.