Create 8_String_to_Integer_(atoi).cc

cpppy · web-flow · commit 6e0e3b6974f4 · 2016-08-23T19:26:42.000+08:00
diff --git a/8_String_to_Integer_(atoi).cc b/8_String_to_Integer_(atoi).cc
@@ -0,0 +1,37 @@
+class Solution {
+public:
+    int myAtoi(string str) {
+        int result=0;
+        int k=1;
+        int count_k=0;
+        int count_val=0;
+        int count_dig=0;
+        for (int i = 0; i<str.size(); ++i){
+            if(str[i]=='-') {
+                k=k*(-1);
+                count_k++;
+            }
+            if(str[i]=='+') {
+                count_k++;
+            }
+            if(str[i]!=' ') count_val++;
+            if(::isdigit(str[i])){
+                count_dig++;
+                int tmp=result;
+                result = result * 10 + (str[i]-'0');
+                if (k>0&&(result<tmp||count_dig>10)) {
+                    result = 2147483647;
+                    break;
+                }
+                if(k<0&&(result<tmp||count_dig>10)){
+                    result= 2147483648;
+                    break;
+                }
+            }
+            if(::isalpha(str[i])||(str[i]==' '&&count_val!=0))   break;
+	    }
+	    if(count_k>1)   k=0;
+	    result=result*k;
+	    return result;
+    }
+};
