P2394 yyy loves Chemistry I

# yyy loves Chemistry I

## Background

Because I will eat the car back , So I put it in the title description ~

## Title Description

[ The story background ]

Once upon a time , There's a man named yyy, He especially likes chemistry , Especially some are very dangerous (zuo) risk (si) The experiment of .

[ Background ]

This day , He began to work out a magical and interesting equation

2Na + 2H2O ==== 2NaOH + H2↑

[ Problem description ]

Now? yyy The mass of a piece is xg Put a lot of sodium into the water , Then start collecting hydrogen .

Final , We know , later , The sodium disappeared in the water . and yyy A bad , All the hydrogen has been collected .

** Every known investment 23 Gram of sodium , Will generate 1 Grams of hydrogen .**

So now yyy How many grams of hydrogen are collected ?

## Input format

a line , A real number x, representative yyy How many grams of sodium are put into the water

The end of the input file line must be ** Can't ** One of them has returned ~

## Output format

a line , A real number ( Round to the nearest 8 Decimal place ), Represents how many grams of hydrogen are produced

## Examples #1

### The sample input #1

```
0.23
```

### Sample output #1

```
0.01000000
```

## Tips

[ Data scale ]

about 100% The data of ,0<x<=1

[ Tips ]

Do you want to know x Are there any decimals ? I won't give it to you >\_<

All I know is that the space limit is 4M, The time limit is 0.1s, And if you read all the numbers down, it might MLE Slightly ~

kkksc: No data range ! Input files do not exceed 5M!

The author : How can it be like this ! Bad review ! I can't dig a hole !

【 translate 】

Enter a Dead man Very long real numbers x, Output x/23 Retain 8 A decimal value .

【AC Code 】

#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iomanip>
#include<iostream>
#include<map>
#include<queue>
#include<string>
#include<vector>
using namespace std;
long double x;
signed main()
{
	scanf("%15Lf",&x);
	cout<<fixed<<setprecision(8)<<x/23;	
	return 0;
}

 

  learn Before Lesson , Before writing the code this time, I have done a good job of adjusting the accuracy Get ready . 

Pay attention to it

 【 High level practices 】

 

#include <iostream>
#include <cstdio>
using std::scanf;
using std::printf;
int x;
char c;
int len(int a) // The length of the returned number 
{
	if (a==0)
		return 1;
	int ans=0;
	while (a)
	{
		++ans;
		a/=10;
	}
	return ans;
}
int main()
{
    if ((c=getchar())=='1') // Special judgement 
    {
    	long double y=1;
		printf("%.8Lf", y/23);
    	return 0;
    }
    getchar();
    bool flg=false;
    for (int i=1; i<=9; ++i)
	{
		if (!flg)
			c=getchar();
		if (c>'9'||c<'0')
			x*=10, flg=true;
		else
			x=(x<<3)+(x<<1)+c-'0';
	}
	x=(x/23+5)/10; // rounding 
	putchar('0');
	putchar('.');
	int length=len(x);
	for (int i=1; i<=8-len(x); ++i) // Fill in the leading zero 
		putchar('0');
	printf("%d\n", x);
	return 0;
}

selected from Yingchuyin bucket rubber Tarragon konjak A man （ Tangled to play a man ） Of TJ.

Yuan Longping ： The biggest mistake of my life is to let Yingchuyin bucket rubber Chinese people have nothing to do when they are full of food

——MC Square man