大数减法c++完美版

最新推荐文章于 2024-07-17 15:31:16 发布

原创最新推荐文章于 2024-07-17 15:31:16 发布 · 307 阅读

0 ·

CC 4.0 BY-SA版权

本文介绍了一种用于比较两个字符串大小并执行大数减法的C++算法。该算法首先通过比较字符串长度和逐字符比较来确定两数大小，然后进行大数减法运算，确保结果的正确性和精度。

#include
#include
#include
using namespace std;
int mintery(string num1, string num2)
{
if (num1.size() > num2.size())
return 1;
else if(num1.size() < num2.size())
return -1;
for (int i = num1.size() - 1;i >= 0;i–)
{
if (num1[i] > num2[i])
return 1;
else if (num1[i] < num2[i])
return -1;
}
return 0;
}
int main()
{
string num1;
string num2;
cin >> num1 >> num2;
for (char &a : num1)
a -= ‘0’;
for (char &a : num2)
a -= ‘0’;
reverse(num1.begin(), num1.end());
reverse(num2.begin(), num2.end());
int flag = mintery(num1, num2);
if (flag == -1)
{
cout << “-”;
swap(num1, num2);
}
if (flag == 0)
{
cout << “0”;
return 0;
}
string res(num1.size()+1, 0);
int total = 0;
for (int i = 0;i < num1.size();i++)
{
total = num1[i] + 10 - num2[i] + res[i];
res[i] = total % 10;
res[i + 1] = total / 10 - 1;
}
for (int i = res.size()-1;i >= 0;i–)
{
if (res[i])
break;
else
res.pop_back();
}
reverse(res.begin(), res.end());
for (char &a : res)
a += ‘0’;
cout << res;
return 0;
}