Java Program

You will be reading a line of data either using .hasNext until user enters -1

number operator number

-1

Read in all numbers as double, and when input has correct syntax output a double. You will never have more than 3 arguments per line.

You first echo the input followed by = and then output (don't echo -1 when at EOF)...

If you don't get a number, you need to throw a NumberFormatException, When you create the number format exception you will be using the constructor NumberFormatException( "Format is number operator number. You entered: " + BadArgument ); When an illegal number has been typed you need to output toString in NumberFormatException and then read the next line of text. Don't check for other exceptions.

Legal operators are: +,-,* and /. If you need get a legal operator . You need to throw an InputMismatchException, you will be using the constructor IllegalArgumentException( "Legal operators are +,-,* and /. You entered: " + BadArgument ). When an illegal operator has been entered you need to output toString in IllegalArgumentException and then read the next line of text. Don't check for other exceptions.

Third argument needs to be a number repeat 1.

On correct input output the solution.

You will read multiple lines in a file, keep reading until EOF or if you read a single -1 from an input line. When you reach EOF or read in only a -1, call System.exit( -1 ).

For each legal line read print out a line with the result of the operation. For example...

Input	Output lines
3 + 2	3 + 2=5.00
2 / 3	2 / 3=0.67
2 + 2abc	2 + 2abc=java.lang.NumberFormatException: Format is number operator number. You entered: 2abc
2	2=java.util.NoSuchElementException
3 ^ 4	3 ^ 4=java.util.InputMismatchException: Legal operators are +,-,* and /. You entered: ^
2 /3	2 /3=java.util.InputMismatchException: Legal operators are +,-,* and /. You entered: /3
2 / 0	2 / 0=Infinity
	=java.util.NoSuchElementException
-1	quit no output

----------------------------------------Here's how it should look like:---------------------------------------- 

Sample Run 1 (User enters 4 + 5 then 4 -5 then 4x then -1 "4 + 5 4 - 5 4x -1 " ): 4 + 5 4 + 5=9.00 4 - 5 4 - 5=-1.00 4x 4x=java.lang.NumberFormatException: Format is number operator number. You entered: 4x -1 Sample Run 2 User Enters: "2 + 3 2 + 2 ^ 3 2 / 0 2 + abc -1 "; 2 + 3 2 + 3=5.00 2 + 2 +=java.util.NoSuchElementException 2 ^ 3 2 ^ 3=java.util.InputMismatchException: Legal operators are +,-,* and /. You entered: ^ 2 / 0 2 / 0=Infinity 2 + abc 2 + abc=java.lang.NumberFormatException: Format is number operator number. You entered: abc Sample Run 3 uses the input String data = "2 + 3 3 ^ 7 2 abc + 2 2x * 2 3 + 6 "; 2 + 3=5.00 3 ^ 7=java.util.InputMismatchException: Legal operators are +,-,* and /. You entered: ^ 2=java.util.NoSuchElementException abc + 2=java.lang.NumberFormatException: Format is number operator number. You entered: abc 2x * 2=java.lang.NumberFormatException: Format is number operator number. You entered: 2x 3 + 6=9.00 

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Hints...

I did all parsing and reading using Scanner. (Scanner has built in Pattern checking such as hasNext, and hasNextInt. );

hasNext needs a Pattern not a RegExp string, i.e., hasNext( Pattern.compile( "\\{|\\[" ) );

I put my try loop inside a infinite while loop, you can have multiple catch statements after the while loop.

For all exception except EOF you are outputting a line with toString for the exception.

For floating point numbers, Infinity is default output of number / 0.0, IEEE 754 defines infinity for double, integers don't have infinity.

I'm using the standard "%,.2f" for output of calculations

Note when your throw the above exception, you need to enter the respective imports, Netbeans is not importing them.

You can use javax.script.ScriptEngine.eval to determine value, I didn't.