问题描述

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 Rⁿwhere R is a real number ( 0.0 < R < 99.999 ) and n is an integer such that 0 < n <= 25.

要求

输入

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.

输出

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.

思路

本题为高精度计算问题，需要将输入的字符串转换为数组，按照四则运算的方式进行运算，具体代码如下所示：

1 #include
        
           2 #include
         
            3 #include
          
             4   5 using namespace std;  6   7 struct bign{  8     int data[1000];  9     int length; 10     int point; 11     bign(){ 12         memset(data, 0, sizeof(data)); 13         length = 0; 14         point = 0; 15     } 16 }; 17  18 string str; 19 int n; 20  21 bign Change(){ 22     bign a; 23     a.point = str.length() - str.find('.') - 1; 24     int j = 0; 25     for(unsigned int i=0;i
           
            =zero;i--){ 82             if(zero==rs.point){ 83                 ans.insert(ans.end(), rs.data[i] + '0'); 84             } 85             else{ 86                 if(i==rs.point){ 87                     ans.insert(ans.end(), rs.data[i] + '0'); 88                     ans.insert(ans.end(), '.'); 89                 } 90                 else{ 91                     ans.insert(ans.end(), rs.data[i] + '0'); 92                 } 93             } 94         } 95     } 96     else{ 97         ans.insert(ans.end(), '.'); 98         for(int i=rs.point-1;i>=zero;i--){ 99             ans.insert(ans.end(), rs.data[i] + '0');100         }101     }102     cout<
            
             <
             
              >str>>n){107 bign bg = Change();108 bign rs = power(bg, n);109 show(rs);110 }111 return 0;112 }
             
            
           
          
         
        

 在解题过程中，遇到的是尾部零处理和首部零处理问题，要注意的是，除了题中所给的样例，10.00之类的幂次需要考虑，这类测试数据，在尾部零处理中，不应该含小数点。