1、输入两个字符串数据,返回加法运算后的值?
public static String addStrings(String num1, String num2) {StringBuilder res = new StringBuilder();int i = num1.length() - 1;int j = num2.length() - 1;int carry = 0;while (i >= 0 || j >= 0 || carry != 0) {/**字符’0’的ascii码是48*数字0的值是0*所以’0’和0差48*num1.charAt(i) - '0'是为了转换字符到数字*/int x = i >= 0 ? num1.charAt(i) - '0' : 0;int y = j >= 0 ? num2.charAt(j) - '0' : 0;int sum = x + y + carry;res.append(sum % 10); //保存当前位的值carry = sum / 10; //保存进到上一位的值i--;j--;}return res.reverse().toString();}public static void main(String[] args) {System.out.println(addStrings("123", "456")); // 输出: 579System.out.println(addStrings("999", "1")); // 输出: 1000}