C++代码

#include<iostream>
#include<string>
#include<cstdlib>

class BigInt {
public:
    BigInt(int data = 0)
    {
        m_data[0] = 0;

        if (data == 0) {
            m_len = 1;

            return;
        }

        int idx = 0;
        while (data > 0) {
            m_data[idx++] = data % 10;
            data /= 10;
        }

        m_len = idx;
    }

    BigInt operator=(BigInt b)
    {
        m_len = b.m_len;

        for (int i=0; i<m_len; ++i) {
            m_data[i] = b.m_data[i];
        }
    }

    void scan()
    {
        std::string strInt;

        std::cin >> strInt;

        m_len = strInt.size();

        for(int i=0; i<m_len; ++i) {
            m_data[i] = strInt[m_len - i - 1] - '0';
        }
    }

    void print()
    {
        for (int i=m_len-1; i>=0; --i) {
            std::cout << m_data[i];
        }
    }

    void push_back(int num)
    {
        if(m_len == 1 && m_data[0] == 0) {
            m_data[0] = num;

            return;
        }

        for(int i=m_len-1; i>=0; --i) {
            m_data[i+1] = m_data[i];
        }

        m_data[0] = num;
        ++m_len;
    }

    BigInt operator+=(const BigInt& b)
    {
        m_len = std::max(m_len, b.m_len);

        for (int i=0; i<b.m_len; ++i) {
            m_data[i] += b.m_data[i];
            m_data[i+1] += m_data[i] / 10;
            m_data[i] %= 10;
        }

        if (m_data[m_len] != 0) {
            ++m_len;
        }

        return *this;
    }

private:
    static const int MAX_LEN = 1e5 + 10;

    int m_data[MAX_LEN];
    int m_len;
};

BigInt operator+(BigInt a, BigInt b)
{
    BigInt c(a);

    c += b;

    return c;
}

int main()
{
    BigInt a;
    BigInt b;
    BigInt c;

    a.scan();
    b.scan();

    c = a + b;

    c.print();

    return 0;
}