在下面的代码中,我预期不需要在最后一个 else 块中初始化变量 a 和 b,但编译器不允许这样做。
import java.util.Random;
public class Foo {
private void foo () {
double a,b;
boolean c;
double r = (new Random()).nextDouble();
if(r < 0.25) {
a = 1;
b = 2;
c = true;
} else if(r >= 0.25 && r < 0.75) {
a = 3;
b = 3;
c = true;
} else {
// why is it necessary to init a and b here?
// given that c is set to false
c = false;
}
if(c) {
double k = a + b;
}
}
}
使用以上代码,编译器会报错。
bash-3.2$ javac Foo.java
Foo.java:25: variable a might not have been initialized
double k = a + b;
^
Foo.java:25: variable b might not have been initialized
double k = a + b;
^
2 errors
我本以为编译器可以进行静态分析,从而确定当c
设置为false时,k
不会被评估。那么我的问题是,为什么编译器要求我初始化a
和b
?