public class Solution {
public int StrToInt(String str) {
if (str.length() == 0) {
return 0;
}
char[] arr = str.toCharArray();
int flag = 0;
if (arr[0] == '+') {
flag = 1;
}
boolean tmp = false;
if (arr[0] == '-') {
tmp = true;
}
int sum = 0;
if (flag == 1 || tmp == true) {
for (int i = 1; i < arr.length; i++) {
if (arr[i] < '0' || arr[i] > '9') {
return 0;
}
sum += (arr[i] - '0') * Math.pow(10, arr.length - i - 1 );
}
} else {
for (int i = 0; i < arr.length; i++) {
if (arr[i] < '0' || arr[i] > '9') {
return 0;
}
sum += (int)(arr[i] - '0') * Math.pow(10, arr.length - i - 1) ;
}
}
return tmp ? sum * (-1) : sum;
}
}