1 #include <iostream>
2 #include<deque>
3 #include<string>
4
5 using namespace std;
6
7 string add(string a, string b) //此函数默认a的长度大于b(可以在main函数里用if语句控制a的长度大于b)
8 {
9 deque<int>sum; //sum用来存储和的每一位
10 int carry = 0; //carry表示进位
11 int i = a.length()-1;
12 int j = b.length()-1;
13 for(; i >= 0,j >= 0; --i,--j)
14 {
15 int wei_sum = (a[i] - '0') + (b[j] - '0') + carry; //wei_sum表示a,b每个对应相同的位相加的和
16 if(wei_sum >= 10)
17 {
18 carry = 1;
19 sum.push_front(wei_sum-10);
20 }
21 else
22 {
23 carry = 0;
24 sum.push_front(wei_sum);
25 }
26
27 }
28 for(int k = a.length()-b.length()-1; k >= 0; --k) //算a比b长的那部分的和
29 {
30 int wei_sum = (a[k] - '0') + carry; //此处一定要加上之前的进位值！因为之前的carry有可能为1.
31 if(wei_sum >= 10)
32 {
33 carry = 1;
34 sum.push_front(wei_sum-10);
35 }
36 else
37 {
38 carry = 0;
39 sum.push_front(wei_sum);
40 }
41 }
42 if(carry == 1)
43 sum.push_front(1);
44
45 string Sum;
46 for(auto d: sum)
47 Sum = Sum + char(d + '0'); //把sum转化为string
48 return Sum;
49 }
50
51
52
53 int main()
54 {
55 string a,b;
56 cin >> a >> b;
57 if(a.length() > b.length())
58 cout << a << " + " << b << " = " << add(a,b);
59 else
60 cout << a << " + " << b << " = " << add(b,a);
61
62 return 0;
63 }
