Q5.2

第1种方法：#include <iostream>
#include <cmath>
#include <stack>
#include <queue>
using namespace std;

stack<int> st;
queue<int> q;

const int maxn = 30;

void print(string &s)
{
	char ch[20];
	strcpy(ch, s.c_str());
	float n = atof(ch);
	int integer = (int)n;
	float decimal = n - integer;
	int t;

	while(integer >= 2)
	{
		t = integer % 2;
		st.push(t);
		integer /= 2;
	}
	st.push(integer);
	while (decimal != 0)
	{
		if(q.size() > maxn)
		{
			cout << "ERROR" << endl;
			return;
		}
		decimal *= 2;
		t = int(decimal);
		q.push(t);
		if(decimal >= 1)
			decimal -= 1;
	}

	while (!st.empty())
	{
		cout << st.top();
		st.pop();
	}
	cout << '.';

	while (!q.empty())
	{
		cout << q.front();
		q.pop();
	}
}

int main(void)
{
	string s;
	cin >> s;
	
	print(s);

	return 0;
}

第二种方法：

#include <iostream>
#include <cmath>

using namespace std;

const int maxn = 30;

string print(string &s)
{
	char ch[20];
	strcpy(ch, s.c_str());
	double n = atof(ch);
	int integer = (int)n;
	float decimal = n - integer;
	int t;
	string intres = "", decires = "", res = "";

	while(integer > 0)
	{
		t = integer % 2;
		if(t)
			intres = "1" + intres;
		else
			intres = "0" + intres; 
		integer /= 2;
	}

	while (decimal > 0)
	{
		decimal *= 2;

		if(decimal >= 1)
		{
			decires += "1";
			decimal -= 1;
		}
		else
			decires += "0";
		if(decires.size() > 30)
			return "ERROR";		
	}

	return intres + "." + decires;
}

int main(void)
{
	string s;
	cin >> s;
	
	string re = print(s);
	cout << re << endl;

	return 0;
}