Create 8. String to Integer(atoi).cpp

Author: ZengruiWang

8. String to Integer(atoi).cpp

@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int myAtoi(string str) {
+        long long res = 0;
+        int end = str.find_first_not_of(' ', 0);
+        if(end == str.length() || (str[end] != '+' && str[end] != '-' && !isdigit(str[end]))) 
+            return 0;
+        int sign = str[end] == '-' ? -1 : 1;
+        if(!isdigit(str[end])) end++;
+        while(isdigit(str[end])){
+            res = res * 10 + (str[end++] - '0') * sign;
+            if(res >= INT_MAX) return INT_MAX;
+            else if(res <= INT_MIN) return INT_MIN;
+        }
+        return res;
+    }
+};