PRoblem Descr
iption
I have a very simple problem for you. Given two integers A and B, your job is to calculate the Sum of A + B.
Input
The first line of the input contains an integer T(1<=T<=20) which means the number of test cases. Then T lines follow, each line consists of two positive integers, A and B. Notice that the integers are very large, that means you should not process them by using 32-bit integer. You may assume the length of each integer will not exceed 1000.
Output
For each test case, you should output two lines. The first line is "Case #:", # means the number of the test case. The second line is the an equation "A + B = Sum", Sum means the result of A + B. Note there are some spaces int the equation. Output a blank line between two test cases.
Sample Input
2
1 2
112233445566778899 998877665544332211
Sample Output
Case 1:
1 + 2 = 3
Case 2:
112233445566778899 + 998877665544332211 = 1111111111111111110
用string保存数字
#include<iostream>
#include<string>
using namespace std;
string add(string &a, string &b)
{
int c = 0;//进位
if (a.size() < b.size()) return add(b, a);
a.assign(a.rbegin(), a.rend());
b.assign(b.rbegin(), b.rend());
int low = 0;
while (low < b.size())
{
int temp = (a[low] + b[low]-'0'-'0' + c) / 10;
a[low] = (a[low] + b[low] - '0' - '0' + c) % 10+'0';
c=temp;
low++;
}
while (low < a.size())
{
int temp = (a[low]-'0' + c) / 10;
a[low] = (a[low] -'0'+c) % 10+'0';
c = temp;
low++;
}
if (c == 1)
a.push_back('1');
a.assign(a.rbegin(), a.rend());
return a;
}
int main()
{
string a, b;
int N;
cin >> N;
for (int t = 1;t <= N;t++)
{
if (t != 1) cout << endl;
cin >> a >> b;
printf("Case %d:\n%s + %s = ", t, a.c_str(), b.c_str());
cout << add(a, b) << endl;
}
}