gistfile1.txt

/*You are required to complete this method */

class GfG
{
    int atoi(String str)
    {
        int number = 0;
        if (str.length() == 0)
            return -1;
        for (int i = 0; i< str.length() ; i++ ) {
            int c = str.charAt(i);
            if (  !(c >= 48 && c<= 57)) {
                return -1;
            } else {
                number = (c-48)*(Math.pow(10, (str.length() - 1 - i ))) + number;
            }
        }
	return number;
    }
}