Write up a detailed solution to the problem: Design a program to convert a Roman
ID: 3807169 • Letter: W
Question
Write up a detailed solution to the problem:
Design a program to convert a Roman numeral to a decimal
number. The program should read a Roman numeral. You
may read it as a string or one character at a time. Do
the conversion and then output the decimal number.
Here are the “letters” you need to know:
Symbol = Value
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1,000
1. Code the pseudocode design as written into C++.
2. Develop test data to prove whether or not the design works. You may use the Roman Numeral-Decimal calculator at this website to create your test data http://www.csgnetwork.com/csgromancnv.html (Links to an external site.) Include test data that tests for all the subtractive exception only values ( 4, 9, 40, 90, 400, and 900, which are written as IV, IX, XL, XC, CD, and CM respectively ) as well as the additive cases. Summarize your results - the summary can be very simple. "I coded and tested your design it (does or doesn't work)."
4. Submit the source code, test data that shows if the code works or not, and your summary for the design
If the design does not work :
1. explain what changes you would have to make to the design to make it work
2. incorporate the changes into the pseudocode.
3. code the new design and use your test data to prove it works.
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Problem
Design a program to convert a Roman numeral to a decimal number. The program should read a Roman numeral. You may read it as a string or one character at a time. Do the conversion and then output the decimal number.
Here are the “letters” you need to know:
Symbol Value
I 1
V 5
X 10
L 50
C 100
D 500
M 1,000
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Design #1
Start
string romanNumeral
num decimalNumber equals 0
num previousNumber equals 0
num currentNumber equals 0
output “Enter number: ”
input romanNumeral
loop from counter equals (romanNumeral length - 1) to 0
test romanNumeral at counter
first case : I
set currentNumber equal to 1
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 1
second case : V
set currentNumber equal to 5
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 5
third case : X
set currentNumber equal to 10
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 10
fourth case : L
set currentNumber equal to 50
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 50
fifth case : C
set currentNumber equal to 100
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 100
sixth case : D
set currentNumber equal to 500
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 500
seventh case : M
set currentNumber equal to 1000
if previousNumber is greater than currentNumber
decimalNumber equals decimalNumber minus currentNumber
else
decimalNumber equals decimalNumber plus currentNumber
set previousNumber equal to 1000
Force decimalNumber to show decimal point and set the precision to the desired number of decimal places
Output decimalNumber
end
-------
Design #11
Variables:
string enteredNumerals
char numeral
int value1
int value2
int result = 0
Output a prompt to enter the number in Roman numerals
Read the input into enteredNumerals
Assign the first character in the string to numeral
Use a switch statement to assign the correct integer value to value1 based
on the character that was entered
While a counter (starting at 1) is less than the length of the string
Read the next character into numeral
Use another switch statement to convert the numeral to an integer and
assign it to value2
If value2 is greater than value 1
result = result + (value2 - value1)
end if
else
result = result + value1
if counter is equal to the length of the string - 1
result = result + value2
end if
end else
value1 = value2
increment counter
endwhile
if result = 0
output value1
end if
else
output result
end else
Explanation / Answer
try this
#include <iostream>
#include <string>
using namespace std;
struct Roman_Number
{
public:
string get()
{
return roman_Number;
}
void show()
{
cout << "Converted Roman Number is " << roman_Number << endl;
}
Roman_Number(const string &input)
{
roman_Number = input;
}
int convert_value()
{
int length = roman_Number.length();
int previous = 0;
bool error = false;
int nIndex = 0;
sum = 0;
while( (error == false) && (nIndex < length) )
{
switch(roman_Number[nIndex])
{
case 'M':
sum += 1000;
if(previous < 1000)
{
sum -= 2 * previous;
}
previous = 1000;
break;
case 'D':
sum += 500;
if(previous < 500)
{
sum -= 2 * previous;
}
previous = 500;
break;
case 'C':
sum += 100;
if(previous < 100)
{
sum -= 2 * previous;
}
previous = 100;
break;
case 'L':
sum += 50;
if(previous < 50)
{
sum -= 2 * previous;
}
previous = 50;
break;
case 'X':
sum += 10;
if(previous < 10)
{
sum -= 2 * previous;
}
previous = 10;
break;
case 'V':
sum += 5;
if(previous < 5)
{
sum -= 2 * previous;
}
previous = 5;
break;
case 'I':
sum += 1;
if(previous < 1)
{
sum -= 2 * previous;
}
previous = 1;
break;
default:
cout << roman_Number[nIndex] << " is not a Entry Romal Numeral" << endl;
error = true;
sum = 0;
}
nIndex++;
}
return sum;
}
int length()
{
return roman_Number.length();
}
private:
string roman_Number;
int sum;
};
int main()
{
string myInput;
int value;
cout << "Please enter the Roman Numeral to convert : ";
cin >> myInput;
Roman_Number myRoman_Number(myInput);
value = myRoman_Number.convert_value();
cout << "Roman Numeral " << myInput << " equals " << value <<endl;
}
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