Roman to Integer Conversion in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the integer value of the Roman numeral 'I'.

DSA C

int romanToInt(char * s) {
    if (s[0] == 'I') {
        return [1];
    }
    return 0;
}

Drag options to blanks, or click blank then click option'

A1

B0

C10

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 0 instead of 1 for 'I'.

Confusing 'I' with 'V' or 'X'.

The Roman numeral 'I' equals 1, so the function should return 1.

2fill in blank

medium

Complete the code to get the integer value of a single Roman numeral character.

DSA C

int value(char r) {
    switch(r) {
        case 'I': return 1;
        case 'V': return 5;
        case 'X': return 10;
        case 'L': return 50;
        case 'C': return 100;
        case 'D': return 500;
        case 'M': return 1000;
        default: return [1];
    }
}

Drag options to blanks, or click blank then click option'

A-1

B1

C0

D1000

Attempts:

3 left

💡 Hint

Common Mistakes

Returning -1 which may cause incorrect calculations.

Returning 1 which is a valid numeral value and may cause confusion.

If the character is not a valid Roman numeral, returning 0 is safe to indicate no value.

3fill in blank

hard

Fix the error in the loop condition to correctly iterate over the string until the end.

DSA C

int romanToInt(char * s) {
    int total = 0;
    int i = 0;
    while (s[i] [1] '\0') {
        total += value(s[i]);
        i++;
    }
    return total;
}

Drag options to blanks, or click blank then click option'

A!=

B==

C<

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' which stops immediately if first char is not '\0'.

Using '<' or '>' which are invalid for char comparison here.

The loop should continue while the current character is not the null character '\0'.

4fill in blank

hard

Fill both blanks to correctly subtract when a smaller numeral precedes a larger one.

DSA C

int romanToInt(char * s) {
    int total = 0;
    int i = 0;
    while (s[i] != '\0') {
        int s1 = value(s[i]);
        if (s[i + 1] != '\0') {
            int s2 = value(s[i + 1]);
            if (s1 [1] s2) {
                total += s2 - s1;
                i += [2];
            } else {
                total += s1;
                i++;
            }
        } else {
            total += s1;
            i++;
        }
    }
    return total;
}

Drag options to blanks, or click blank then click option'

A<

B2

C>

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<' for comparison.

Incrementing i by 1 instead of 2 after subtraction.

If the current value is less than the next, subtract current from next and move two steps ahead.

5fill in blank

hard

Fill all three blanks to create a dictionary-like structure mapping Roman numerals to integers using arrays.

DSA C

typedef struct {
    char symbol;
    int value;
} RomanMap;

RomanMap map[] = {
    {'I', [1],
    {'V', [2],
    {'X', [3]
};

Drag options to blanks, or click blank then click option'

A1

B5

C10

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up values for 'V' and 'X'.

Using incorrect integer values.

The Roman numerals 'I', 'V', and 'X' correspond to 1, 5, and 10 respectively.