【www.bbyears.com--js教程】
基本操作符
precedence operator description association
1 ++,-- postincrement, postdecrement r -> l
2 ++,-- preincrement, predecrement r -> l
+,- unary plus, unary minus r -> l
~ bitwise compliment r -> l
! boolean not r -> l
3 new create object r -> l
(type) type cast r -> l
4 *,/,% multiplication, division, remainder l -> r
5 +,- addition, subtraction l -> r
+ string concatenation l -> r
6 <<, >>, >>> left shift, right shift, unsigned right shift l -> r
7 <, <=, >, >= l -> r
instanceof type comparison l -> r
8 ==, != value equality and inequality l -> r
==, != reference equality and inequality l -> r
9 & boolean and l -> r
& bitwise and l -> r
10 ^ boolean xor l -> r
^ bitwise xor l -> r
11 | boolean or l -> r
| bitwise or l -> r
12 && conditional and l -> r
13 || conditional or l -> r
14 ?: conditional ternary operator l -> r
15 =,+=,-=, assignment operators r -> l
*=,/ =,%=,
&=,^=, |=,
<<=, >> =,
>>>=
运算符的优先级
operator precedence group associativity operator precedence
(), [], postfix ++, postfix -- left highest
unary +, unary -, prefix ++, prefix --, ~, ! right
(type), new left
*, /, % left
+, - left
<<, >>, >>> left
< ,<= , >, >=, instanceof
==, !=
& left
^ left
| left
&& left
|| left
?: left
=, +=, -=, *=, /=, %=, <<=, >>=, >>>=, &=, |=, ^= right lowest
public class mainclass {
public static void main(string[] arg) {
int count = 1;count += 5;
system.out.println(count);count = count + 5;
system.out.println(count);}
}
结果
+=
-=
*=
/=
%=
<<=
>>=
>>>=
&=
|=
^=
条件运算
if(value > conditionvalue){
result = result1;
}else{
result = result2;
}logical_expression ? expression1 : expression2
public class mainclass {
public static void main(string[] args) {
int v = 1;
system.out.println(v == 1 ? "a" : "b");v++;
system.out.println(v == 1 ? "a" : "b");
}
}
下面综合上面的运算符特点，我们做个实题。
public class mainclass {
public static void main(string[] a){
booltest(true, false);
chartest("x", "y");
bytetest((byte)0, (byte)1);
shorttest((short)0, (short)1);
inttest(1, 2);
longtest(11l, 22l);
floattest(1.1f, 2.2f);
doubletest(1.1, 2.2);
}// to accept the results of a boolean test:
static void f(boolean b) {
system.out.println("f:"+b);
}
static void booltest(boolean x, boolean y) {
// arithmetic operators:
//! x = x * y;
//! x = x / y;
//! x = x % y;
//! x = x + y;
//! x = x - y;
//! x++;
//! x--;
//! x = +y;
//! x = -y;
// relational and logical:
//! f(x > y);
//! f(x >= y);
//! f(x < y);
//! f(x <= y);
f(x == y);
f(x != y);
f(!y);
x = x && y;
x = x || y;
// bitwise operators:
//! x = ~y;
x = x & y;
x = x | y;
x = x ^ y;
//! x = x << 1;
//! x = x >> 1;
//! x = x >>> 1;
// compound assignment:
//! x += y;
//! x -= y;
//! x *= y;
//! x /= y;
//! x %= y;
//! x <<= 1;
//! x >>= 1;
//! x >>>= 1;
x &= y;
x ^= y;
x |= y;
// casting:
//! char c = (char)x;
//! byte b = (byte)x;
//! short s = (short)x;
//! int i = (int)x;
//! long l = (long)x;
//! float f = (float)x;
//! double d = (double)x;
}
static void chartest(char x, char y) {
// arithmetic operators:
x = (char)(x * y);
x = (char)(x / y);
x = (char)(x % y);
x = (char)(x + y);
x = (char)(x - y);
x++;
x--;
x = (char)+y;
x = (char)-y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
x= (char)~y;
x = (char)(x & y);
x = (char)(x | y);
x = (char)(x ^ y);
x = (char)(x << 1);
x = (char)(x >> 1);
x = (char)(x >>> 1);
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
x <<= 1;
x >>= 1;
x >>>= 1;
x &= y;
x ^= y;
x |= y;
// casting:
//! boolean b = (boolean)x;
byte b = (byte)x;
short s = (short)x;
int i = (int)x;
long l = (long)x;
float f = (float)x;
double d = (double)x;
}
static void bytetest(byte x, byte y) {
// arithmetic operators:
x = (byte)(x* y);
x = (byte)(x / y);
x = (byte)(x % y);
x = (byte)(x + y);
x = (byte)(x - y);
x++;
x--;
x = (byte)+ y;
x = (byte)- y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
x = (byte)~y;
x = (byte)(x & y);
x = (byte)(x | y);
x = (byte)(x ^ y);
x = (byte)(x << 1);
x = (byte)(x >> 1);
x = (byte)(x >>> 1);
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
x <<= 1;
x >>= 1;
x >>>= 1;
x &= y;
x ^= y;
x |= y;
// casting:
//! boolean b = (boolean)x;
char c = (char)x;
short s = (short)x;
int i = (int)x;
long l = (long)x;
float f = (float)x;
double d = (double)x;
}
static void shorttest(short x, short y) {
// arithmetic operators:
x = (short)(x * y);
x = (short)(x / y);
x = (short)(x % y);
x = (short)(x + y);
x = (short)(x - y);
x++;
x--;
x = (short)+y;
x = (short)-y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
x = (short)~y;
x = (short)(x & y);
x = (short)(x | y);
x = (short)(x ^ y);
x = (short)(x << 1);
x = (short)(x >> 1);
x = (short)(x >>> 1);
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
x <<= 1;
x >>= 1;
x >>>= 1;
x &= y;
x ^= y;
x |= y;
// casting:
//! boolean b = (boolean)x;
char c = (char)x;
byte b = (byte)x;
int i = (int)x;
long l = (long)x;
float f = (float)x;
double d = (double)x;
}
static void inttest(int x, int y) {
// arithmetic operators:
x = x * y;
x = x / y;
x = x % y;
x = x + y;
x = x - y;
x++;
x--;
x = +y;
x = -y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
x = ~y;
x = x & y;
x = x | y;
x = x ^ y;
x = x << 1;
x = x >> 1;
x = x >>> 1;
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
x <<= 1;
x >>= 1;
x >>>= 1;
x &= y;
x ^= y;
x |= y;
// casting:
//! boolean b = (boolean)x;
char c = (char)x;
byte b = (byte)x;
short s = (short)x;
long l = (long)x;
float f = (float)x;
double d = (double)x;
}
static void longtest(long x, long y) {
// arithmetic operators:
x = x * y;
x = x / y;
x = x % y;
x = x + y;
x = x - y;
x++;
x--;
x = +y;
x = -y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
x = ~y;
x = x & y;
x = x | y;
x = x ^ y;
x = x << 1;
x = x >> 1;
x = x >>> 1;
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
x <<= 1;
x >>= 1;
x >>>= 1;
x &= y;
x ^= y;
x |= y;
// casting:
//! boolean b = (boolean)x;
char c = (char)x;
byte b = (byte)x;
short s = (short)x;
int i = (int)x;
float f = (float)x;
double d = (double)x;
}
static void floattest(float x, float y) {
// arithmetic operators:
x = x * y;
x = x / y;
x = x % y;
x = x + y;
x = x - y;
x++;
x--;
x = +y;
x = -y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
//! x = ~y;
//! x = x & y;
//! x = x | y;
//! x = x ^ y;
//! x = x << 1;
//! x = x >> 1;
//! x = x >>> 1;
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
//! x <<= 1;
//! x >>= 1;
//! x >>>= 1;
//! x &= y;
//! x ^= y;
//! x |= y;
// casting:
//! boolean b = (boolean)x;
char c = (char)x;
byte b = (byte)x;
short s = (short)x;
int i = (int)x;
long l = (long)x;
double d = (double)x;
}
static void doubletest(double x, double y) {
// arithmetic operators:
x = x * y;
x = x / y;
x = x % y;
x = x + y;
x = x - y;
x++;
x--;
x = +y;
x = -y;
// relational and logical:
f(x > y);
f(x >= y);
f(x < y);
f(x <= y);
f(x == y);
f(x != y);
//! f(!x);
//! f(x && y);
//! f(x || y);
// bitwise operators:
//! x = ~y;
//! x = x & y;
//! x = x | y;
//! x = x ^ y;
//! x = x << 1;
//! x = x >> 1;
//! x = x >>> 1;
// compound assignment:
x += y;
x -= y;
x *= y;
x /= y;
x %= y;
//! x <<= 1;
//! x >>= 1;
//! x >>>= 1;
//! x &= y;
//! x ^= y;
//! x |= y;
// casting:
//! boolean b = (boolean)x;
char c = (char)x;
byte b = (byte)x;
short s = (short)x;
int i = (int)x;
long l = (long)x;
float f = (float)x;
}
}