qyf这题有点太过于简单了，17行代码过 #include<bits/stdc++.h> using namespace std; int main(){ map<int,char>i_c;char intral[100],fratral[100];long long intion,k,intemp=0,fratemp=0,flag=0;long double all,fration; for(int i=0;i<10;i++)i_c[i]=i+'0'; for(char i='A';i<='Z';i++)i_c[i-'A'+10]=i; cin>>all>>k; intion=(long long)all; fration=all-intion; while(intion){intral[intemp++]=i_c[intion%k];intion/=k;} if(fration>0)flag=1; while(fration!=(long long)fration&&fratemp<21){fratral[fratemp++]=i_c[(long long)(frationk)];fration=frationk-(long long)(frationk);} fratral[fratemp++]=i_c[(long long)(frationk)]; for(int i=intemp-1;i>=0;i--)cout<<intral[i]; if(flag){cout<<'.';for(int i=0;i<fratemp-1;i++)cout<<fratral[i];} return 0; }