Roman to Integer Conversion in DSA C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the value of the Roman numeral 'IV'?

The value of 'IV' is 4. 'I' before 'V' means 1 is subtracted from 5.

beginner

Explain the subtraction rule in Roman numerals.

If a smaller numeral appears before a larger one, subtract the smaller from the larger. For example, 'IX' is 9 (10 - 1).

intermediate

What is the integer value of 'MCMXCIV'?

'MCMXCIV' equals 1994. Breakdown: M(1000) + CM(900) + XC(90) + IV(4).

intermediate

In C, how can you map Roman numerals to their integer values efficiently?

Use a function or array to map characters 'I', 'V', 'X', 'L', 'C', 'D', 'M' to 1, 5, 10, 50, 100, 500, 1000 respectively.

beginner

Why do we check the next Roman numeral character when converting to integer?

To decide if we add or subtract the current numeral's value. If the next numeral is larger, subtract current; else add it.

What integer does the Roman numeral 'XL' represent?

A 40

B 60

C 90

D 50

'XL' means 10 before 50, so 50 - 10 = 40.

Which Roman numeral represents the number 100?

A D

B L

C C

D M

'C' stands for 100 in Roman numerals.

In Roman to integer conversion, what do you do if the current numeral is smaller than the next one?

A Add current numeral's value

B Subtract current numeral's value

C Ignore current numeral

D Multiply current numeral's value

If current numeral is smaller than next, subtract it to handle cases like 'IV' or 'IX'.

What is the integer value of 'D' in Roman numerals?

A 500

B 50

C 100

D 1000

'D' represents 500.

Which of these is NOT a valid Roman numeral?

A MMXV

B CM

C XLII

D IC

'IC' is invalid because 'I' cannot be subtracted from 'C' directly.

Describe the step-by-step process to convert a Roman numeral string to an integer.

Think about how subtraction rule affects addition.

Explain why the Roman numeral 'IX' equals 9 and not 11.

Look at the order of numerals and their values.