精確計算100的階乘（C++）

#include <iostream><br />#include <vector></p><p>using namespace std;</p><p>void calc(vector<int>& v);<br />void print_result(const vector<int>& v);</p><p>int main() {<br />vector<int> v;<br />calc(v);<br />print_result(v);<br />return 0;<br />}</p><p>void calc(vector<int>& v) {<br />v.push_back(1);<br />for(int i = 1; i <= 100; ++i) {<br />const int len = static_cast<int>(v.size());<br />for(int j = 0; j < len; ++j) {<br />v[j] *= i;<br />}</p><p>for(int j = 0; j < len - 1; ++j) {<br />if(v[j] >= 10) {<br />v[j + 1] += v[j] / 10;<br />v[j] %= 10;<br />}<br />}</p><p>if(v[len - 1] >= 10) {<br />int carry = v[len - 1] / 10;<br />v[len - 1] %= 10;<br />do {<br />v.push_back(carry % 10);<br />carry /= 10;<br />} while (carry > 0);<br />}<br />}<br />}</p><p>void print_result(const vector<int>& v) {<br />const int len = static_cast<int>(v.size());<br />for(int i = len - 1; i >= 0; --i) {<br />cout << v[i];<br />}<br />cout << endl;<br />}