public int stringToInteger(String str) {

// get the distance between a integar and it char

int interval = 0 - '0';

int result = 0;

int lowerBoundary = 0;

if (str.charAt(0) == '-'){

lowerBoundary = 1;

}

for (int i = str.length() - 1; i >= lowerBoundary; i--) {

result += ((int) str.charAt(i) + interval) * getWeight(str.length() - 1 - i);

}

if (lowerBoundary == 0){

return result;

} else {

return -1 * result;

}

}

public int getWeight(int n) {

if (n == 0) {

return 1;

}

return 10 * getWeight(n - 1);

}

public static void main(String[] args) {

// TODO Auto-generated method stub

}