1. Problem Statement
Create a program that contains a function to calculate the square root of a number.
2. Requirements
2.1 Assumptions
Written in C++
Only use command line input/output
User will input real numbers only
User will input only ‘y’ or ‘n’ when asked to repeat
2.2 Specifications
The program will prompt the user to input a real number
For valid real number input
Calculate the square root
For invalid input
If input is negative
Terminate program
Decomposition Diagram
Program
Input
User inputs real number via command line
User inputs ‘y’ or ‘n’ character
Process
Determine if input is valid
Use series approximation to calculate sqrt(x)
Output
Print result of square root operation
Print error for invalid data
Test Strategy
Valid Data
Invalid Data
5. Test Plan Version 1
Test Strategy
#
Description
Input
Expected
Actual
Pass/Fail
Output
Output
Valid Data
1
squareRoot() at minimum possible
Valid Data
2
squareRoot() above minimum
Valid Data
3
squareRoot() higher order
Valid Data
4
squareRoot() EVEN HIGHER
Invalid Data
1
squareRoot() below minimum
Initial Algorithm
Create Square Root Function squareRoot()
Parameter
Double Input x
Method
Assert that input is greater than 0
Calculate Square root via series approximation
Set Xn equal to 2x
Evaluate such that xn+1 = (xn + xxn ) / 2
Keep evaluating until xn − xn+1 < 0.0001
Return Root Value
Create main()
Prompt user to input double to use
Run squareRoot()
Prompt user if they would like to calculate again
If input is ‘y’
Run again
If input is ‘n’
Exit
7. Test Plan Version 2
Test Strategy
#
Description
Input
Expected
Actual
Pass/Fail
Output
Output
Valid Data
1
squareRoot() at minimum possible
0
0
Valid Data
2
squareRoot() above minimum
1
1
Valid Data
3
squareRoot() higher order
3
~sqrt(3)
Valid Data
4
squareRoot() EVEN HIGHER
16
4
Invalid Data
1
squareRoot() below minimum
-3
assert()
