public class jh_07_ concept expression {
public static void main (String [] args) {
/ *
* are composed of a sequence of symbols and operands.
10 *
* A;
* A = 10;
* A + B * 10
* the content can be an expression assigned to a variable.
SUM = A + B *
* 10 = X
* + X * Y = 2. 1
* /
}
}
Assignment exchange between the two values {public class jh_o8_ variable
public static void main (String [] Arge) {
// swap values of the variables.
/ *
* Interchangeable left and right hands.
* Ideas:
* 1: put one hand (left) put something on the table;
* 2: put your other hand (right) thing to the left.
* 3: to put things on the table to the right hand;
* ------
* left hand -------- Table
* -------- right hand;
* the table ------ - right hand;
* /
int a = 10; // left;
int = B. 8; // the right;
// declare a variable showing a table;
int TEMP;
// ------- left the table;
// tables left =
TEMP = A;
// ------- left hand
A = B;
// ------- Table right;
B = TEMP;
System.out.println (A);
the System.out. the println (B);
}
}
public class jh_09_ arithmetic operators {
public static void main (String [] args) {
/ *
* plus
* minus
* Multiplication
* except
* modulo (or called modulo)
* /
int = A. 7;
int. 4 = B;
SUM = A + B int;
System.out.println (1000);
int Money = 1000;
System.out.println (Money);
System.out.println (SUM);
System.out.println (A + B); plus //
System.out.println (a - b); // Save
System.out.println (a * b); // multiplication
// integer other integer or integers.
System.out.println (a / b); // other
//% Remainder - to actually divide the left and right, return the remainder.
System.out.println (A & B);
// input from the console 3 course grade students Hao
int stb = 99, java = 88 , sql = 76;
int cha = java - sql;
double avq = (stb + java + sql)/3.0;
System.out.println("----------");
System.out.println("STB\tJAVA\tSQL");
System.out.println(stb + "\t" + java+"\t"+sql);
System.out.println("----------");
System.out.println("成绩差："+cha);
System.out.println("平均分："+avg);
}
}
public static void main (String [] args) {
// compound assignment operators + = - * /%
int. 5 A =, B = 2;
System.out.println (A);
A + = b; // do the left and right of the adder, and then assigned to the left
// A = A + B
the System.out .println (A);
A - = B;
A * = B;
A / = B;
A =% B;
/ *
* = + later for accumulating sum
*. 1 + 2 + +. 5. 4. 3 +
* (. 1 + 2) +. 3
* SUM +. 3
* SUM = SUM +. 3;
* SUM + =. 3;
* ( (. 1 + 2) +. 3). 4 +
* + SUM. 4;
* SUM = SUM +. 4;
* SUM + =. 4;
*
* = I. 1
* SUM = 0;
*
* Sum + = i;
Print * (sum)
* i = 2;
* Sum + = i;
* - sum = 3
* i = 3;
* Sum + = i;
*
* /
}
public static void main (String [] args) {
/ * Save Save the Comparative jerk
* +: increase since. Data be added to 1
* -: decrement. Save the original data 1
* /
/ * using involved in computing separate Comparative
* 1: alone: on the back and front of the operands the same effect. (Common)
* 2: Participation operations using:
* on the front of the operands, the first increment-decrement and then participate in the operations.
* On the back of the operands, the first operation participate, then increment decrement.
* /
Int = A. 5;
System.out.println (A);. 5 //
int B = 2;
System.out.println (B); 2 //
System.out.println ( "======= == ");
//System.out.println (A ++);
// add A ++ itself. 1
//System.out.println (B -);
// B - Save itself. 1
int count = 0;
// count ++；
//System.out.println(count);
// count --;
//System.out.println(count);
}
public static void main (String [] args) {
int a =. 5;
int = B. 5;
int X = a * 2 ++;
System.out.println (X) ;
int Y = B * 2;
System.out.println (Y);
/ *
* A ++ do first operation itself and then adding 1
* ++ A is to add more 1, then do calculation
* /
the System .out.println (A);
System.out.println (B);
//System.out.println (A ++); //. 5
// ++ A first output is then coupled. 1
//System.out. println (++ b);
// b ++ first and then add 1 to their own output.
// b ++;
//
// No matter what is on their own plus 1
// System.out.println (A);
// System.out.println (b);
}
/ *
* 1: block: {----} braces content
* 2: Function: function to complete a specific block of code
* the nextInt ();
*. 3: use the function calls . The object name in the function name ();
* 4: Scanner keyboard input object.
Scanner Scanner new new SC = * (the System.in);
. * Object name function name ();
* sc.nextInt ();
* A = sc.nextInt int ();
*
* /
public static void main (String [] args ) {
// create a keyboard input objects
Scanner Scanner new new SC = (the System.in);
System.out.println ( "enter a value of:");
// in a console input integer,
// this input integer assigned to a.
B = 10 int;
int sc.nextInt A = ();
System.out.println (A);
}
/ * score for the first time a student 81.29,
* a second multi attained during the first 2 minutes,
* find second fraction?
* /
Public static void main (String [] args) {
// first fraction 81.29
Double firstScore = 81.29;
// second fraction than the first two points a plurality
Double secondScore;
secondScore firstScore = + 2;
/ *
* 2 2.0 ----
* 2.0 ----- 2
* /
// output:
System.out.println ( "second fraction is:" + secondScore);
Double a = 2;
System.out.println (A);
// automatic conversion implicit conversion
// mandatory ---- ---- ----
}
public static void main (String [] args) {
// Apple notebook market share last year was 20,
int lastyear = 20;
// this year's growing market share is 9.8
Double thisYear = + lastyear 9.8;
// can be converted
// int thisYear = (int) thisYear + 9.8;
// (int) (lastyear + 9.8)
// lastyear + 9.8
// class. Types of.
thisYear lastyear + = int (int) 9.8;
}
}
/ * input from the console classmate Zhang achievements,
* and John Doe score (80 points) compared
* Output "Joe Smith John Doe score higher than the score it?"
* the determination result
* /
public static void main (String [] args) {
// new new Scanner Scanner SC = (the System.in);
// Zhang score input from the console
int a = 10;
System.out.println (a );
System.out.println ( "Please enter Joe Smith's achievement:");
int zhangScore = 80;
// John Doe and scores (80) points relatively
// John Doe score (80)
int liScore = 80;
// John Doe John's score is higher than the scores?
zhangScore the Result = boolean> liScore;
// output
System.out.println (+ result "high?");
/ *
* the amount of consumption of each product sum * Discount
* /
public static void main (String [] args) {
// Product Name
String tx = "T Xu";
String WQX = "tennis shoes";
String WQP = "racket";
// monovalent
int txPrice = 245;
int wqxPrice = 570;
int = 320. wqpPrice;
// number
int txNum = 2;
int = wqxNum. 1;
int. 1 = wqpNum ;
// calculate the amount of each item;
int * txNum txMoney = txPrice;
int * wqxNum wqxMoney = wqxPrice;
int * wqpNum wqpMoney = wqpPrice;
// output theme upper part.
System.out .println ( "************* consumption single *************");
System.out .println ( "purchase items \ t Price \ t the number \ t amount ");
System.out .println (tx +" \ t ¥ "+ txPrice +" \ t "+ txNum +" \ t ¥ "+ txMoney);
System.out .println (WQX +" \ T ¥ "+ wqxPrice +" \ T "+ wqxNum +" \ T ¥ "+ wqxMoney);
the System.out .println (WQP +" \ T ¥ "+ wqpPrice +" \ T "+ wqpNum +" \ T ¥ "+ wqpMoney);
// given a discount
double discount = 0.8; // 8 off
// calculate the total amount of consumption allmoney ----:
Double allmoney = (+ wqpMoney wqxMoney txMoney +) * discount;
// given actual payment amount 1500
int Money = 1500;
// calculation give change. leftMoney;
Double leftMoney = Money - allmoney;
// calculate points. 100 3 points.
System.out.println ( "discount \ t" + (int) ( discount * 10) + " discount");
System.out.println ( "total amount of consumption: ¥" + allmoney);
System.out.println ( " give change: \ t "+ leftMoney);
System.out.println (" points: \ t "+ integral);
/ *
* 1: variable name given nine. Store content.
* 2: Output screenshot upper part
* 3: do arithmetic.
* 4: The output of the operational result.
* /
}