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.
