void f() {
int i;
i++;
}
## 成员变量初始化方式之一————默认初始化:
public class InitialValues {
boolean t;
char c;
byte b;
short s;
int i;
long l;
float f;
double d;
InitialValues reference;
void printInitialValues() {
System.out.println(
"Data type Initial value"
);
System.out.println(
"boolean "
+ t);
System.out.println(
"char["
+ c +
"]"
);
System.out.println(
"byte "
+ b);
System.out.println(
"short "
+ s);
System.out.println(
"int "
+ i);
System.out.println(
"long "
+ l);
System.out.println(
"float "
+ f);
System.out.println(
"double "
+ d);
System.out.println(
"reference "
+ reference);
}
public static void main(String[] args) {
new
InitialValues().printInitialValues();
}
}
输出:
Data type Initial value
boolean
false
char[]
byte 0
short 0
int 0
long 0
float 0.0
double 0.0
reference
null
## 成员变量初始化方式之二————显式赋值:
public class InitialValues2 {
boolean bool =
true
;
char ch =
'x'
;
byte b = 47;
short s = 0xff;
int i = 999;
long lng = 1;
float f = 3.14f;
double d = 3.14159;
}
## 成员变量初始化方式之三————调用对象进行初始化赋值:
class Depth {
}
public class Measurement {
Depth d =
new
Depth();
}
## 成员变量初始化方式之四————调用方法进行初始化赋值:
public class MethodInit {
int i = f();
int f() {
return
11;
}
}
public class MethodInit2 {
int i = f();
int j = g(i);
int f() {
return
11;
}
int g(int n) {
return
n * 10;
}
}