POJ1001

感觉写的太乱了，用了多层函数，基本是下面这个结构

int main()

{

	int get_num(char r[], short int rn[], int &rn_len)

	int R_e_n(int rn_pb, int n, int rn_len, short int rn[], short int t[]){

		void mul(short int rn[], short int t[], int &t_len, int rn_len)

	}

}

Source Code

Problem: 1001		User: washiwxm
Memory: 252K		Time: 0MS
Language: C++		Result: Accepted

• Source Code

  #include
  
  using namespace std;
  
  #define N 10
  #define M 150
  
  void mul(short int rn[], short int t[], int &t_len, int rn_len)
  {
         int  res = 0, i, ca = 0, temp_len;
         short int temp[M];
         memset(temp,0,sizeof(short int)*M);
   
         for(i = 0; i < t_len; i++){
                 for(int j = 0; j < rn_len; j++){
                           res = t[i]*rn[j] + ca + temp[i + j];
                           ca = res / 10;
                           temp[i + j] = res % 10;
                           if((j == (rn_len - 1))&&(i != (t_len - 1))){
                                 temp[i + j + 1] = ca;
                                 ca = 0;
                           }else if((j == (rn_len - 1))&&(i == (t_len - 1))){
                                 temp[i + j + 1] = ca;
                           }          
                 }
                      
         }
         if(ca > 0){
               //temp[t_len + rn_len -1] = ca;
               temp_len = t_len + rn_len;
         }else{
               temp_len =  t_len + rn_len -1;
         }
         for(i = 0; i < temp_len; i++){
               t[i] = temp[i];
               //cout<
         }
         //cout<
         t_len = temp_len;
  } 
  
  int R_e_n(int rn_pb, int n, int rn_len, short int rn[], short int t[])
  {
        //所有小数位数 
        
        int t_len = 1;
        t[0] = 1;
        while(n--){
              //每次用R乘以t,将结果存入t
              mul(rn, t, t_len, rn_len);     
        }
  
        return t_len;  
  
         
  } 
  
  
  int get_num(char r[], short int rn[], int &rn_len)
  {
        int i, j, ni;
        //rn_len来传递rn[N]的长度，以免后面重复计算 
        for(rn_len = -1, i = 0; r[i] != '\0'; i++) rn_len++;
        
        //************************
   
        //cout<<"r:"<
        
        i = rn_len;
        while(r[i] == '0'){
                   rn_len--;
                   i--;
        }
        
        
        //将r[N]倒置放入rn[N] 
        for(i = 0, j = 0, ni = 0; i <= rn_len; i++){
              
              if(r[i] != '.') {
                      rn[rn_len - 1 - ni] = r[i] - '0';
                      ni++;                
              }else{
                      j = i;      
              }     
        }
        //rn_len来传递rn[N]的长度，以免后面重复计算 
        //*****************************
        //cout<<"小数位数为"<
        
        //此时i为r[N]的长度，i - j - 1即为小数点后面的位数 
        return (i - j - 1);    
  }    
  
  int main()
  {
      int n;
      //r[N]记录R 
      char r[N];
      short int  rn[N];
      //t[M]存储每次结果 
      short int t[M];
      //t_len存储t的长度  n_pb为小数位数 
      int t_len, rn_pb, i, rn_len, t_pb;
      
      
      memset(r,0,sizeof(short int)*N);
      memset(rn,0,sizeof(short int)*N);
      memset(t,0,sizeof(short int)*M);
      
      //loop
      while(cin>>r>>n){
            //将r[N]转换为rn[N]
            
            rn_pb = get_num(r, rn, rn_len);
            //cout<<"小数位数为："<
            t_len = R_e_n(rn_pb, n, rn_len, rn, t);
            t_pb = n * rn_pb;
            for(i = 0; (i < t_len - t_pb) && (t[t_len - i - 1] == 0); i++){
            }
            for(; i < t_len - t_pb; i++){      
                  cout<<t[t_len - i - 1];
            }
            if (t_pb != 0) cout<<".";
            
            for(i = t_len - t_pb; i < t_len; i++){
                  cout<<t[t_len - i - 1];
            }
            cout<<endl;
                     
            memset(rn,0,sizeof(short int)*N);
            memset(t,0,sizeof(short int)*M);
      }
      
      return 0;
  }