大数相加

public class AddBigNum {
public static char[] addNum(String arr,String brr){
StringBuffer arrRe = new StringBuffer(arr);
StringBuffer brrRe = new StringBuffer(brr);
arr = arrRe.reverse().toString();
brr = brrRe.reverse().toString();
int arrlen = arr.length();
int brrlen = brr.length();
int minlen = arrlen < brrlen ?arrlen:brrlen;
int maxlen = arrlen > brrlen ?arrlen:brrlen;
char[] result =new char[maxlen+1];
boolean isOver = false;
boolean ?flag = false;
if(arrlen < brrlen)
? ?{
? ? ? ?for(int i = arrlen ; i < brrlen ; i++)
? ? ? ?{
? ? ? ? arr += "0";
? ? ? ?}
? ?}
? ?else if (arrlen > brrlen)
? ?{
? ? ? ?for(int i = brrlen ; i < arrlen ; i++)
? ? ? ?{
? ? ? ? brr += "0";
? ? ? ?}
? ?}
for(int i=0;i<maxlen;i++){
int a = Integer.parseInt(""+arr.charAt(i)) + ?Integer.parseInt(""+brr.charAt(i));
? ?if(a >= 10 && !isOver){
? ? isOver = true;
? ? char temp = String.valueOf((a-10)).charAt(0);
? ? result[i] = temp;
? ? continue;
? ?}
? ?if(isOver){
? ? if(a >= 10){
? ? isOver = true;
? ? char temp = String.valueOf((a-10+1)).charAt(0);
? ? result[i] = temp;
? ? isOver = true;
? ?}
? ? if(a+1>=10){
? ? if(i == maxlen-1){
? ? ?result[i+1] = '1';
? ? }
? ? char temp = String.valueOf((a-10+1)).charAt(0);
? ? result[i] = temp;
? ? ? ?isOver = true;
? ? }else{
? ? char temp = String.valueOf((a+1)).charAt(0);
? ? result[i] = temp;
? ? isOver = false;
? ? }
? ?}else{
? ? char temp = String.valueOf(a).charAt(0);
? ? result[i] = temp;
? ? isOver = false;
? ?}
? ?
}

? ?return result;
}
public static void printArr(char[] arr){
for(int i=arr.length-1;i>=0;i--){
System.out.print(arr[i]);
}
}
public static void main(String[] args) {
? ?String str1="748";
? ?String str2="373452";
char[] re = AddBigNum.addNum(str1,str2);
AddBigNum.printArr(re);
}

}

输出：：374200