用字符串模拟两个大数相加——java实现

 用字符串模拟两个大数相加

public String addTwoString(String a, String b) { int lengthA = a.length(); int lengthB = b.length(); int length = lengthA > lengthB ? lengthA : lengthB; // 进位值 int temp = 0; StringBuilder builder = new StringBuilder(); for (int i = 0; i < length; i++) { int elementA = 0; if (i < lengthA) { elementA = Integer.valueOf(String.valueOf(a.charAt(lengthA - 1 - i))); } int elementB = 0; if (i < lengthB) { elementB = Integer.valueOf(String.valueOf(b.charAt(lengthB - 1 - i))); } int value = elementA + elementB + temp; if (value >= 10) { temp = 1; } else { temp = 0; } builder.insert(0, value % 10); } if (temp != 0) { builder.insert(0, temp); } return builder.toString(); }