PKU1001

                                       Exponentiation
Time Limit:500MS  Memory Limit:10000K
Total Submit:16430 Accepted:3691

Description
Problems involving the computation of exact values of very large magnitude and precision
are common. For example, the computation of the national debt is a taxing experience for
many computer systems.

This problem requires that you write a program to compute the exact value of Rn where R
is a real number ( 0.0 < R < 99.999 ) and n is an integer such that 0 < n <= 25.

Input
The input will consist of a set of pairs of values for R and n. The R value will occupy
columns 1 through 6, and the n value will be in columns 8 and 9.

Output
The output will consist of one line for each line of input giving the exact value of R^n.
Leading zeros should be suppressed in the output. Insignificant trailing zeros must not be
printed. Don't print the decimal point if the result is an integer.

Sample Input

95.123 12
0.4321 20
5.1234 15
6.7592  9
98.999 10
1.0100 12

Sample Output

548815620517731830194541.899025343415715973535967221869852721
.00000005148554641076956121994511276767154838481760200726351203835429763013462401
43992025569.928573701266488041146654993318703707511666295476720493953024
29448126.764121021618164430206909037173276672
90429072743629540498.107596019456651774561044010001
1.126825030131969720661201

Hint
If you don't know how to determine wheather encounted the end of input:
s is a string and n is an integer

#include<iostream>
using namespace std;
int Length(int a)
{  

 int k=0;
    while(a/10!=0){k++;a=a/10;}
 return k+1;
}
int main()
{
 double a;
 int n;
 while(cin>>a>>n)
 {
  
  long int at[5000],bt[5000];
  int btl;
  int dot=0;
        double ae=a;
  
        if(Length((int)a)==1){dot=4;a=a*10000;}
  else {dot=3;a=a*1000;}
       
       
  dot=dot*n;
    
  int k=a;
  long int g=a;
 
  int i=Length(k),j=4999;
        btl=i;
  while(i>0)
  {
   bt[j--]=k%10;
   k=k/10;
   i--;
  }
  if(n==1){ cout<<ae<<endl;continue;}
  else n--;
  while(n-->0)
  {  
              
   k=0;
   j=4999;
   j=j-btl+1;
            while(k<btl){at[k++]=bt[j];bt[j]=0;j++;}
   k--;
   j=4999;
   while(k>=0)
   {
    bt[j-1]=(at[k]*g+bt[j])/10;
    bt[j]=(at[k]*g+bt[j])%10;
    k--;
    j--;
   }
            int m=bt[j];
   while(m>0)
   {  
    bt[j--]=m%10;
    m=m/10;
   }
   btl=4999-j;
  }
        if(j+1>4999-dot)
   {   cout<<".";
    for(int t=0;t<dot+j-4999;t++)
     cout<<0;
    
   }

        int te=4999;
  while(bt[te]==0&&te>4999-dot)te--;
  int ie=te;
 
  for(int it=j+1;it<=ie;it++)
  {
   
  
   if(it==4999-dot&&ie!=4999-dot)
   {
    cout<<bt[it]<<".";
   }
   else cout<<bt[it];
  

  }
    
  cout<<endl;
 }
 
return 0;
}