北大oj1001

[为卿狂]

我的代码我拿他给的例子验证了，没问题，就是老是通不过，求大神们帮帮忙，关于高精度的问题。

原题：
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


代码：
#include <iostream>
#define LEN 1000
using namespace std;

void show(string str , int n)
{
int count ,co,j = 0,num =0;
int a[LEN] , b[LEN] , c[LEN] ;
for(int i = 0 ; i<LEN ; i++)
{
a[i]= 0;
b[i]= 0;
c[i]= 0;

}

for(int i = str.size()-1 ; i>=0 ; i--)
{
if(str[i] == '.')
{
num=str.size()-(i+1);
//cout<<"*******"<<num<<endl;
continue;
}

a[j] = (int)str[i]-'0';
b[j] = (int)str[i]-'0';
j++;
}
int l = n * str.size();
for(int k = 0 ; k<n-1 ; k++)
{
for(int i = 0 ; i < l ; i++)
{
c[i] = 0;
}

for(int i = 0 ; i < l ; i++)
{
for(int j = 0 ; j<=i ; j++)
{

c[i]+=a[j] * b[i-j] ;
}
}

for(int i = 0 ; i < l ; i++)
{
if(c[i]>=10)
{
c[i+1]+=c[i]/10;
c[i] = c[i]%10;
}
}
for(int i = 0 ; i<l ; i++)
{
b[i] = c[i];
}

}

for(int i = 0 ; i < l ; i++)
{
if(c[i]>=10)
{
c[i+1]+=c[i]/10;
c[i] = c[i]%10;
}
}
for(count = l ; count >=0 ; count --)
{
if(c[count] != 0 )
break;

}
if(num)
{
for(int i = count ; i>=num*n; i--)
{
cout<<c[i];
}
for(co = 0 ; co <=num*n ; co ++)
{
if(c[co] != 0 )
{
break;
}
}
if(co<num*n)
{
cout<<".";

for(int i = num*n-1 ; i>=co; i--)
{
cout<<c[i];
}
}
}
else
{

for(int i = count ; i>=0; i--)
{
cout<<c[i];
}
}

}

int main()
{
string str ;
int n;

//while(cin>>str>>n)
while(cin>>str>>n)
{

show(str, n);
cout<<endl;
//cout<<"***********"<<str.size();
}

return 0;
}


错误：
Main.cpp
F:\temp\13807277.230743\Main.cpp(116) : error C2679: binary '>>' : no operator found which takes a right-hand operand of type 'std::string' (or there is no acceptable conversion)
istream(1000): could be 'std::basic_istream<_Elem,_Traits> &std::operator >><std::char_traits<char>>(std::basic_istream<_Elem,_Traits> &,signed char *)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(1007): or 'std::basic_istream<_Elem,_Traits> &std::operator >><std::char_traits<char>>(std::basic_istream<_Elem,_Traits> &,signed char &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(1014): or 'std::basic_istream<_Elem,_Traits> &std::operator >><std::char_traits<char>>(std::basic_istream<_Elem,_Traits> &,unsigned char *)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(1021): or 'std::basic_istream<_Elem,_Traits> &std::operator >><std::char_traits<char>>(std::basic_istream<_Elem,_Traits> &,unsigned char &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(155): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(std::basic_istream<_Elem,_Traits> &(*)(std::basic_istream<_Elem,_Traits> &))'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(161): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(std::basic_ios<_Elem,_Traits> &(*)(std::basic_ios<_Elem,_Traits> &))'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(168): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(std::ios_base &(*)(std::ios_base &))'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(175): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(std::_Bool &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(194): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(short &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(228): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(unsigned short &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(247): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(int &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(273): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(unsigned int &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(291): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(long &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(309): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(__w64 unsigned long &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(329): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(__int64 &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(348): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(unsigned __int64 &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(367): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(float &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(386): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(double &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(404): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(long double &)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(422): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(void *&)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
istream(441): or 'std::basic_istream<_Elem,_Traits> &std::basic_istream<_Elem,_Traits>::operator >>(std::basic_streambuf<_Elem,_Traits> *)'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
while trying to match the argument list '(std::istream, std::string)'
F:\temp\13807277.230743\Main.cpp(116) : fatal error C1903: unable to recover from previous error(s); stopping compilation

[Falleyes]

建议你去看看别人的博客，研究研究别人的代码。 研究的过程中，你就会发现你的代码问题在哪儿了。 示例链接

[toma2008]

C小学生都喜欢发作文帖上来, 但是没人愿意帮你改作文呢 你可以先编译一段程序,成功了,再编译另一段程序,不行再打断点看问题在哪