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String to Integer (atoi) Test | Pre-employment assessment - Testlify
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String to Integer (atoi) Test

Overview of String to Integer (atoi) Test

The problem involves converting a string to an integer, considering signs, digits, and edge cases like overflow. it's crucial for parsing text inputs into usable numerical values, addressing whitespace, signs, and potential errors .

Skills measured

  • greedy
  • string

Available in



Coding Test


10 Mins





Use of String to Integer (atoi) test

The problem involves converting a string to an integer, considering signs, digits, and edge cases like overflow. It's crucial for parsing text inputs into usable numerical values, addressing whitespace, signs, and potential errors.
The solution starts by checking if the input string is empty. If it is, the function returns 0 immediately. Otherwise, a long long variable ret is used to temporarily store the converted value.
The istringstream is used to stream the input string, and the >> operator is employed to extract an integer value into the ret variable. This extraction takes care of ignoring leading whitespace and handling optional signs.
Subsequently, the code checks whether ret is smaller than the minimum value of INT_MIN. If this condition is met, ret is set to INT_MIN to prevent integer underflow. Similarly, if ret is greater than the maximum value of INT_MAX, it is capped to INT_MAX to avoid integer overflow.
Finally, the function returns the adjusted value of ret, which ensures the integer returned is within the valid range of a 32-bit signed integer.
In summary, this solution employs an istringstream for string-to-integer conversion and addresses integer overflow and underflow by adjusting the result if needed. This approach provides a way to handle common scenarios and produce accurate integer results from input strings.

Relevant for

  • Software Developer Engineer
  • Software Developer
  • Software Engineers

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The greedy skill covered in the String to Integer (atoi) problem involves continuously reading characters from the input string and converting them into an integer until a non-numeric character is encountered. This skill is important because it allows us to efficiently process the input string without unnecessary backtracking. By greedily parsing the input string, we can convert it into an integer without needing to store intermediate results or backtrack if an invalid character is encountered. This approach simplifies the implementation of the algorithm and improves its overall efficiency.



One important string skill covered in String to Integer (atoi) is parsing and converting a string representation of a number into an integer. This skill is crucial for handling user input in applications where numerical data needs to be processed. By converting strings to integers, we can perform mathematical operations, comparisons, and other calculations accurately. Additionally, converting strings to integers allows us to validate and sanitize input data, ensuring that the program functions correctly and securely. Mastering this skill is essential for developing robust and reliable software applications.

The String to Integer (atoi) test is created by a subject-matter expert

Testlify’s skill tests are designed by experienced SMEs (subject matter experts). We evaluate these experts based on specific metrics such as expertise, capability, and their market reputation. Prior to being published, each skill test is peer-reviewed by other experts and then calibrated based on insights derived from a significant number of test-takers who are well-versed in that skill area. Our inherent feedback systems and built-in algorithms enable our SMEs to refine our tests continually.

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