1073. Scientific Notation (20)

#include<cstdio>#include<iostream>#include<string>#include<sstream>using namespace std;int main (){string s,ans="";getline(cin,s);if (s[0]=='-')ans+=s[0];int indexE=s.find("E");string num=s.substr(1,indexE-1);char x=s[indexE+1];string exp=s.substr(indexE+2,s.size()-indexE-2);stringstream ss;ss<<exp;int e;ss>>e;if (e==0){cout<<ans<<num<<endl;return 0;}if (x=='+'){if (e<num.size()-2){ans=ans+num[0]+num.substr(2,e)+'.'+num.substr(e+2,num.size()-e-2);}else {ans=ans+num[0]+num.substr(2,num.size()-2);for(int i=0;i<e-num.size()+2;i++)ans+="0";}}if (x=='-'){ans=ans+"0.";while (e--!=1)ans+="0";ans=ans+num[0]+num.substr(2,num.size()-2);}cout<<ans<<endl;//}

分析：和基础题一样，这次学习了一个更加简洁的方法，主要熟悉运用substr 以及sstream