Java Learning Note 2

The five-spoke operator

Arithmetic operators

+ Plus

-Minus

* Multiply

/except

% take-up (modulo) (the remainder depends on the positive or negative of the molecule)

arithmetic operator int x1 = 10;int Y1 = 3; System.out.println (x1/y1);//The result is an integer//cast result of a double type of System.out.println (x1/(double) y1);// The remainder (the positive and negative depends on the positive or negative of the molecule) System.out.println (x1%y1); System.out.println (-X1%Y1); System.out.println (-X1%-Y1);

Self-increment auto-decrement operator

++n first operation, then value

n++ first value, then arithmetic

N=n+1

--n first operation, then value

n--first value, then arithmetic

N=n-1

Self-increment System.out.println (x1++),//First output 10, then ++system.out.println (++x1),//First + +, then output 12system.out.println (--X1);//First--, Re-output 11system.out.println (x1--),//First output 11, then--system.out.println (x1);//Output 10

Relational operators

> Greater than

< less than

>= greater than or equal to

<= less than or equal to

= = equals

! = does not equal

logical operators

&& and

|| Or

! Non -

Expression 1| | Expression 2, if expression 1 is true, the expression 2 does not need to be judged. If the expression 1 is false, you need to determine the expression 2.

if (++x1 > | | y1--< 3) {System.out.println ("x=" +x1+ ", y=" +y1);}

Difficulty bit operator

& After bitwise and conversion to binary, two number of the same column is 1 o'clock, 1; otherwise 0

| After a bitwise or conversion to binary, the two-digit same column is 0 o'clock, 0; otherwise 1

~ After bitwise inversion to binary, 0 is converted to 1, 1 is converted to 0

^ After bitwise XOR or conversion to binary, two numbers are the same as the same column, 0; not 1

>> right shift equals except 2

<< left shift equals multiply by 2

Note: The highest bit of the computer is displayed as a sign bit, 0 is positive, and 1 is negative

Negative complement = anti-code +1

Anti-code = In addition to the sign bit, you take the counter

The bitwise operator int x2 = 10;int y2 = 7;int Z2 = x2&y2;//is converted to binary, the two-digit same column is 1 o'clock, 1; otherwise 0system.out.println (z2); int z3 = z2|y2; System.out.println (Z3);//After conversion to binary, the two-digit same column is 0 o'clock, which is 0; otherwise 1int z4 = Z2^y2; System.out.println (Z4);//Convert to binary, two number same column, 0; not 1int z5 = ~x2; System.out.println (Z5);//convert to binary, 0 to 1, 1 to 0, negative complement = anti-code +1, anti-code = except for the sign bit, you take the inverse int z6 = x2>>2; System.out.println (z6); int z7 = x2<<2; System.out.println (Z7);

Assignment operators

variable = expression

VI. SELECT statement structure

Java Learning Note 2