C. Exponential notation

题目连接：

http://www.codeforces.com/contest/691/problem/C

Description

You are given a positive decimal number x.

Your task is to convert it to the “simple exponential notation”.

Let x = a·10b, where 1 ≤ a < 10, then in general case the “simple exponential notation” looks like “aEb”. If b equals to zero, the part “Eb” should be skipped. If a is an integer, it should be written without decimal point. Also there should not be extra zeroes in a and b.

English alphabet
You are given a string s. Check if the string is “s-palindrome”.

Input

The only line contains the positive decimal number x. The length of the line will not exceed 106. Note that you are given too large number, so you can’t use standard built-in data types “float”, “double” and other.

Output

Print the only line — the “simple exponential notation” of the given number x.

Sample Input

16

Sample Output

1.6E1

Hint

题意

给你一个数字，让你转化成科学计数法

题解：

记录第一个数字出现的位置，最后一个数字出线的位置，点出现的位置

然后瞎统计一下就好了

代码

#include<bits/stdc++.h>
using namespace std;
void p(int x){
    if(x==0)return;
    printf("E%d",x);
}
int main(){
    string s;
    cin>>s;
    int a=-1,b=-1,c=s.size();
    for(int i=0;i<s.size();i++){
        if(s[i]=='.')c=i;
    }
    for(int i=0;i<s.size();i++){
        if(s[i]=='0'||s[i]=='.')continue;
        a=i;break;
    }
    for(int i=s.size()-1;i>=0;i--){
        if(s[i]=='0'||s[i]=='.')continue;
        b=i;break;
    }
    if(a==b){
        printf("%c",s[a]);
        if(c<a)p(c-a);//printf("E%d",c-a);
        else p(c-a-1);//printf("E%d",c-a-1);
        return 0;
    }
    cout<<s[a]<<".";
    for(int i=a+1;i<=b;i++)
    {
        if(s[i]=='.')continue;
        cout<<s[i];
    }
    if(c<a)p(c-a);//printf("E%d",c-a);
    else p(c-a-1);//printf("E%d",c-a-1);
}