Java - Calculator

General description for homework: In this homework, you need to modify the java source code file Calculator.java in chap 9, so that it takes the input parameter in a different way. For example, instead of taking one parameter "7 + 20" as the only argument, the modified version takes three parameters 7 + 20 as the argument list for the main method, and perform the same task of calculating the result for the expression. Here is the detail description for homework 9: No GUI is needed in this homework. No console input is needed, thus no need to import Scanner class. In the main method, then follow the STEPS below:

1. If the number of arguments supplied to the main method is not equal to 3, then output a line that says "Usage: java operand1 operator operand2" , and then quit the program. The program continues to the following steps if the argument number is 3.

2. If the second parameter is none of the following: + , -, x, / , %, then you need to output a line that says: "supported operators are +, -, x, / , and % " , and then quit the program. The symbol x above means multiplication. Attention: we CANNOT use symbol * as multiplication in our homework, and the reason is explained in the "Implementation requirement" below.

3. If the second parameter is any one of the following: + , -, x, / , %, then convert the first and the third parameter to int type, and then perform the required calculation. Save the calculated result to a local variable, and the result should be of int type.

4. Output to the console with the entire expression and calculated result , such as 7 + 20 = 27 Implementation requirement:

• In class java, you should have only one method: the main method. Do not put more classes or more methods in the homework, o/w, you are in the wrong track.

• User Calculator.java as a reference, and feel free to invoke APIs from String/StringBuilder.

• Notice that if the operator is / , and the result is int type, that means the division precision will not be kept. For example, 13 /3 will yield a result of 4.

• Notice that we use symbol x for multiplication operation, and this is different from textbook source code "Calculator.java" that uses symbol * for multiplication. We CANNOT use symbol * for multiplication in this homework, because symbol * has special meaning in command line, when symbol * itself is supplied as an individual String object in the command line.

• Symbol % means the remainder operator, and you can refer to textbook page 46 for explanation of remainder operator.

• Add suitable comments in the source code.

• Please read the above implementation details carefully BEFORE start coding.

• After finishing coding, you need to debug your program and test it multiple times with different input parameters provided for each test run.

• You can use command line to supply the arguments and test the program, or use Eclipse. Either way is fine.