String to Integer atoi in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert the first character of the string to an integer digit.

DSA Python

digit = ord(s[0]) - [1]

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

A97

B65

C48

D32

Attempts:

3 left

💡 Hint

Common Mistakes

Using ASCII code of 'A' or 'a' instead of '0'.

Forgetting to subtract the ASCII code.

The ASCII value of '0' is 48, so subtracting 48 converts the character digit to its integer value.

2fill in blank

medium

Complete the code to check if the character is a digit.

DSA Python

if '0' <= s[i] [1] '9':

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A<

B==

C>=

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of <=.

Using > instead of <=.

To check if s[i] is between '0' and '9', use the <= operator.

3fill in blank

hard

Fix the error in the code to correctly build the integer from the string digits.

DSA Python

num = num [1] 10 + (ord(s[i]) - ord('0'))

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A*

B-

C+

D//

Attempts:

3 left

💡 Hint

Common Mistakes

Using + instead of * for shifting digits.

Using // or - which are incorrect here.

To build the number, multiply the current number by 10 and add the new digit.

4fill in blank

hard

Fill both blanks to correctly handle the sign and start index for parsing.

DSA Python

sign = 1
if s[0] == [1]:
    sign = -1
    i = [2]
else:
    i = 0

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

A'-'

B'+'

C1

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' for sign check.

Not updating the start index after sign.

If the first character is '-', sign is -1 and start parsing from index 1.

5fill in blank

hard

Fill all three blanks to complete the atoi function that converts string to integer.

DSA Python

def my_atoi(s):
    s = s.strip()
    if not s:
        return 0
    sign = 1
    i = 0
    if s[0] == [1]:
        sign = -1
        i = 1
    elif s[0] == [2]:
        i = 1
    num = 0
    while i < len(s) and '0' <= s[i] <= '9':
        num = num [3] 10 + (ord(s[i]) - ord('0'))
        i += 1
    return sign * num

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

A'-'

B'+'

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Not handling '+' sign.

Using '+' instead of '*' when building the number.

The function handles optional '+' or '-' signs and builds the number by multiplying by 10 and adding digits.