https://github.com/lepharamramchiary/string-to-integer-atoi
https://github.com/lepharamramchiary/string-to-integer-atoi
cpp
Last synced: 3 months ago
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- Host: GitHub
- URL: https://github.com/lepharamramchiary/string-to-integer-atoi
- Owner: LepharamRamchiary
- Created: 2023-02-09T08:27:35.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2023-02-09T08:34:26.000Z (over 2 years ago)
- Last Synced: 2024-12-29T20:33:25.849Z (5 months ago)
- Topics: cpp
- Homepage:
- Size: 1.95 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
**# String-to-Integer(atoi)**
```
**Question**:-
Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++'s atoi function).
The algorithm for myAtoi(string s) is as follows:
-Read in and ignore any leading whitespace.
-Check if the next character (if not already at the end of the string) is '-' or '+'. Read this character in if it is either. This determines if the final result is negative or positive respectively. Assume the result is positive if neither is present.
-Read in next the characters until the next non-digit character or the end of the input is reached. The rest of the string is ignored.
-Convert these digits into an integer (i.e. "123" -> 123, "0032" -> 32). If no digits were read, then the integer is 0. Change the sign as necessary (from step 2).
-If the integer is out of the 32-bit signed integer range [-231, 231 - 1], then clamp the integer so that it remains in the range. Specifically, integers less than -231 should be clamped to -231, and integers greater than 231 - 1 should be clamped to 231 - 1.
-Return the integer as the final result.
Note:
-Only the space character ' ' is considered a whitespace character.
-Do not ignore any characters other than the leading whitespace or the rest of the string after the digits.
```
Example 1:
```
Input: s = "42"
Output: 42
Explanation: The underlined characters are what is read in, the caret is the current reader position.
Step 1: "42" (no characters read because there is no leading whitespace)
^
Step 2: "42" (no characters read because there is neither a '-' nor '+')
^
Step 3: "42" ("42" is read in)
^
The parsed integer is 42.
Since 42 is in the range [-231, 231 - 1], the final result is 42.
```
Solution
```
#include
using namespace std;
class Solution
{
public:
int myAtoi(string s)
{
int sign = 1;
int base = 0;
int i = 0;
int n = s.size();
while (i < n && s[i] == ' ')
{
i++;
}
if (s[i] == '-' || s[i] == '+')
sign = 1 - 2 * (s[i++] == '-');
while (s[i] >= '0' && s[i] <= '9')
{
if (base > INT_MAX / 10 || base == INT_MAX / 10 && s[i] - '0' > INT_MAX % 10)
{
if (sign == 1)
{
return INT_MAX;
}
return INT_MIN;
}
else
{
base = (base * 10) + (s[i++] - '0');
}
}
return base * sign;
}
};
int main()
{
Solution ob;
cout << ob.myAtoi("-45") << endl;
cout << ob.myAtoi(" 56") << endl;
cout << ob.myAtoi("100") << endl;
}
```