POJ 1001 高精度乘法运算

 

#include <iostream>#include <string>using namespace std;string Muti(string &s1,string &s2){string result;result.reserve(400);for(int i=0;i<400;++i)result.push_back('0');int pos=0,index=0;for(int i=0;i<s1.length();++i){if(s1[i]=='.')continue;int left=0;index=pos++;for(int j=0;j<s2.length();++j,++index){if(s2[j]=='.'){index--;continue;}int temp=(s2[j]-'0')*(s1[i]-'0')+left;left=(result[index]-'0'+temp)/10;result[index]=(result[index]-'0'+temp)%10+'0';}while(left){int t=left;left=(result[index]-'0'+left)/10;result[index]=(result[index]-'0'+t)%10+'0';++index;}}result.resize(index);return result;}int main(){string s1;int n;int point=0;while(cin>>s1>>n){point=0;for(int i=0;i<s1.length()/2;++i)swap(s1[i],s1[s1.length()-i-1]);if(s1.find('.')!=-1)point=s1.find('.');string result="1";for(int i=0;i<n;++i)result=Muti(s1,result);point*=n;int end=0;for(int i=0;i<point;++i)if(result[i]=='0')++end;elsebreak;int beg=result.length()-1;for(int i=result.length()-1;i>=point;--i)if(result[i]=='0')beg--;elsebreak;for(int i=beg;i>=point;--i)cout<<result[i];if(point!=end){cout<<'.';for(int j=point-1;j>=end;--j)cout<<result[j];}cout<<endl;}return 0;}