写一个大数相加的算法java

在Java中编写大数相加的算法，我们通常会使用字符串处理来避免溢出问题，因为整型数据在相加过程中可能会超出其最大范围。这里提供一个基于字符串的简单算法：

public class BigIntegerAddition {
    public static String addStrings(String num1, String num2) {
        int len1 = num1.length(), len2 = num2.length();
        StringBuilder result = new StringBuilder(len1 + len2);
        int i = len1 - 1, j = len2 - 1;
        int carry = 0;

        while (i >= 0 || j >= 0) {
            int n1 = i >= 0 ? num1.charAt(i--) - '0' : 0; // get digit from first number
            int n2 = j >= 0 ? num2.charAt(j--) - '0' : 0; // get digit from second number

            int sum = n1 + n2 + carry; // calculate sum
            result.append(sum % 10); // append the sum to the result string
            carry = sum / 10; // update carry for next iteration
        }

        // If there's a carry left after adding all digits, add it as leading zero
        if (carry > 0) {
            result.insert(0, carry);
        }

        return result.toString(); // return the final result
    }
}

// 使用示例
public static void main(String[] args) {
    String num1 = "1234567890";
    String num2 = "9876543210";
    System.out.println(addStrings(num1, num2)); // 输出：11111111100
}