如下,是加法的方法。
#include<string>
#include<vector>
#include<algorithm>
#include<iostream>
using namespace std;
template <class T>
void reverse(T& s)
{
int begin = 0;
int end = s.size() - 1;
while (begin < end)
{
swap(s[begin++], s[end--]);
}
}
int atoi(char ch)
{
return ch - '0';
}
void my_main(string &num1, string &num2)
{
vector<int> ret;
if (num1.size() == 0 || num1[0] == '0')
{
for (auto e : num2)
{
cout << e;
}
return;
}
if (num2.size() == 0 || num2[0] == '0')
{
for (auto e : num1)
{
cout << e;
}
return;
}
reverse(num1), reverse(num2);
int i = 0, j = 0, temp = 0;
int len1 = num1.size();
int len2 = num2.size();
ret.reserve(std::max(len1, len2) + 1);
int carry = 0;
for (; i < len1 || j < len2; i++, j++)
{
int first = i < len1 ? atoi(num1[i]) : 0;
int second = j < len2 ? atoi(num2[j]) : 0;
ret.push_back( (first+second + carry) % 10);
if ((first+second+carry) >= 10)
carry = 1;
else
carry = 0;
}
if (carry == 1)ret.push_back(1);
reverse(ret);
for (auto e : ret)
{
cout << e;
}
cout << '\n';
}
int main()
{
string num1, num2;
while (cin >> num1 >> num2)
{
my_main(num1, num2);
}
return 0;
}