Java jobs) 01

One, arithmetic

(a) Design ideas

Use the scanner class to read the runtime user input data, then perform a data type conversion, and then use the output class output after completing the arithmetic.

(ii) Flowchart

(c) Program code

Zhangxiaochen 2015/10 44 The operation

Import Javax.swing.JOptionPane; Import Class Joptionpane

public class Operation {

public static void Main (String args[])

{

String Firstnumber,//First string entered by user

Secondnumber; Second string entered by user

int Number1,//first number to add

Number2,//second number to add

Sum,//Sum of Number1 and number2

Redu,//reduction of Number1 and Number2

Pro Product of Number1 and number2

float Div; Divistor of Number1 and Number2

Read in first number from user as a string

Firstnumber =

Joptionpane.showinputdialog ("Enter first integer");

Read in second number from user as a string

Secondnumber =

Joptionpane.showinputdialog ("Enter second integer");

Convert numbers from type String to type int

Number1 = Integer.parseint (Firstnumber);

Number2 = Integer.parseint (Secondnumber);

Add the numbers

sum = number1 + number2;

Redu=number1-number2;

Pro=number1 * NUMBER2;

Div=number1/number2;

Display the results

Joptionpane.showmessagedialog (

Null

"And yes:" + sum+ "\ n" +

"Difference is:" + redu+ "\ n" +

"Product is:" + pro+ "\ n" +

"Quotient is:" + div+ "\ n",

"Results",

Joptionpane.plain_message);

System.exit (0); Terminate the program

}

}

(iv) operation

Two enumtest

(a) Program code

public class Enumtest {

public static void Main (string[] args) {

Size S=size.small;

Size T=size.large;

S and T refer to the same object?

System.out.println (s==t); //

is the original data type?

System.out.println (S.getclass (). isprimitive ());

Convert from String

Size u=size.valueof ("SMALL");

System.out.println (S==u); True

List all of its values

For (Size value:Size.values ()) {

System.out.println (value);

}

}

}

Enum Size{small,medium,large};

(ii) operation

(iii) Thinking

Enumeration types cannot be directly operated, and type conversions are required to compare sizes or operations.

Three testdouble

(a) Program code

Public class testdouble {

Public Static void Main (String args[]) {

System. out. println ("0.05 + 0.01 =" + (0.05 + 0.01));

System. out. println ("1.0-0.42 =" + (1.0-0.42));

System. out. println ("4.015 * 100 =" + (4.015 * 100));

System. out. println ("123.3/100 =" + (123.3/100));

}

}

(ii) operation

(iii) Thinking

Double type results in loss of data precision due to precision problems

Java jobs) 01