A1073_B1024 Scientific Notation (20 分)

#include <iostream>
#include <string.h>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
  
  char str[10010];
  
  cin.getline(str, 10010);
  int len = strlen(str);
  char c = str[0];
  
  if(c == '-'){
    cout << "-";
  } 
  
  int pos = 0; //位置 
  
  while(str[pos] != 'E'){
    pos++;
  }
  
  int exp = 0; //指数 
  
  for(int i = pos+2; i < len; i++){
    exp = exp * 10 + (str[i] - '0');
  }
  int n = exp;
  //指数为负数 
  if(str[pos+1] == '-'){
    cout << "0.";
    for(int i = 0; i < exp - 1; i++){
      cout << "0";
    }
    for(int i = 1; i < pos; i++){
      if(str[i] != '.'){
        cout << str[i];
      }
    }
  } else {
    int m = 1;
    for(int i = 1; i < pos && i < n+3; i++){
      m++;
      if(str[i] != '.'){
        cout << str[i];
        exp--;
      }
    }
    exp++;
    
    //考虑补0的情况 
    if(exp > 0){
      for(int i = 0; i < exp; i++){
        cout << "0";
      }
    }
     
    if(pos - n - 3 > 0){
      cout << ".";
      for(int i = 0; i < pos - n - 3; i++){
        cout << str[i+m];
      }
    }
  }
  
  return 0;
}