Main topics:

User validated input Basic

String Methods

if & if - else Statements

Loop Statements

Program Specification:

Write a Java program that emulates a simple calculator:

Declare and initialize a String variable (expression) to "0"

Declare and initialize an int variable (resultSoFar) to 0

Display the current expression to the screen

Repeat the following until the ( Exit ) option is selected:

1. Display a menu which gives the user the choice of the following menu options:

1 -> Add 1

2 -> Multiply by 2

3 -> Exit

and uses a user validation loop to read their response into a String variable. Note: You must repeatedly get the users response until it is exactly one of the characters 1 2 3

2. If ( Exit ) was NOT selected:

(a) Add the selected operation string to the end of the expression string: +1 or *2

(b) Add the character ( to the front of the expression string

(c) Add the character ) to the end of the expression string

(d) Display the current expression to the screen

(e) Update the current result of the arithmetic expression: ++resultSoFar or resultSoFar *= 2

Display the entire expression with its result.

Grading:

Performance Indicator [1] [2] [3]

Readability and documentation 1 2 2

Use of loop(s) operators 1 2 2

Functional requirements 2 3 4

Efficiency 1 2 2

Sample run(s):

0

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit

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Choose an operator from the menu above : 1

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(0+1)

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit

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Choose an operator from the menu above : 2

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((0+1)*2)

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit

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Choose an operator from the menu above : 2

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(((0+1)*2)*2) ---------------------------------------------

1 -> Add 1

2 -> Multiply by 2

3 -> Exit

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Choose an operator from the menu above : 1

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((((0+1)*2)*2)+1)

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit ---------------------------------------------

Choose an operator from the menu above : 2

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(((((0+1)*2)*2)+1)*2)

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit ---------------------------------------------

Choose an operator from the menu above : 1

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((((((0+1)*2)*2)+1)*2)+1)

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit

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Choose an operator from the menu above : 2

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(((((((0+1)*2)*2)+1)*2)+1)*2)

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1 -> Add 1

2 -> Multiply by 2

3 -> Exit

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Choose an operator from the menu above : 3

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(((((((0+1)*2)*2)+1)*2)+1)*2) = 22

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