c++二，八，十，十六进制的互相转换（包括小数，负数，且保留小数点后六位）关于本文章内容说明进制间的转换思想功能目的代码实现

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我是靠谱客的博主优美板凳，这篇文章主要介绍c++二，八，十，十六进制的互相转换（包括小数，负数，且保留小数点后六位）关于本文章内容说明进制间的转换思想功能目的代码实现，现在分享给大家，希望可以做个参考。

关于本文章内容说明

文章基本只是将作者本人编写的代码进行复制粘贴，而这份代码是作者大一上学期期末作业，若有不足之处，还请见谅。原因主要还是快到期末了，不想写代码，想着“借鉴”网上大佬们的代码，但是没找到合适的，于是自己就写一份吧。

进制间的转换思想

因为十进制的方便，所以利用十进制作为中间桥梁进行进制之间的转换。对于浮点数进行整数部分与小数部分的分离来计算，并在最后相加。

功能目的

1.各进制数字符串转换为十进制正数值；
2.分离十进制数值的整数和小数部分；
3.对分离出的整数、小数部分分别做转换，将其转换为目标进制；
4将转换好的整数、小数部分以及符号位拼接为字符串输出。

代码实现

菜单项的实现

构建一级菜单，利用循环构建，并且调用二级菜单

复制代码

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void menu()
{
	int n = -1;
	while (n != 0)
	{
		cout << "n**********************";
		cout << "n（1）2进制数转换";
		cout << "n（2）8进制数转换";
		cout << "n（3）10进制数转换";
		cout << "n（4）16进制数转换";
		cout << "n（0）退出";
		cout << "n**********************";
		cout << "n请输入功能号：";
		cin >> n;
		while (n < 0 || n>4)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
			two_menu_1();
		else if (n == 2)
			two_menu_2();
		else if (n == 3)
			two_menu_3();
		else if (n == 4)
			two_menu_4();
		else return;
	}
}

构建二级菜单，并且能够返回上一级菜单，共有四个分别对应（二进制，八进制，十进制，十六进制）

复制代码

void two_menu_1()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）2进制数  --->  8进制数";
		cout << "n（2）2进制数  --->  10进制数";
		cout << "n（3）2进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}//第一个子菜单
void two_menu_2()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）8进制数  --->  2进制数";
		cout << "n（2）8进制数  --->  10进制数";
		cout << "n（3）8进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 16);
			cout << "n16进制数为：" << x << endl;
		}
		else menu();
	}
}
void two_menu_3()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）10进制数  --->  2进制数";
		cout << "n（2）10进制数  --->  8进制数";
		cout << "n（3）10进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}
void two_menu_4()
{
	int n = -1;
	string x;
	while (n != 0) {
		cout << "n*******************************";
		cout << "n（1）16进制数  --->  2进制数";
		cout << "n（2）16进制数  --->  8进制数";
		cout << "n（3）16进制数  --->  10进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			cout << "n10进制数为：" << x;
		}
		else menu();
	}
}

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void two_menu_1()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）2进制数  --->  8进制数";
		cout << "n（2）2进制数  --->  10进制数";
		cout << "n（3）2进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}//第一个子菜单
void two_menu_2()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）8进制数  --->  2进制数";
		cout << "n（2）8进制数  --->  10进制数";
		cout << "n（3）8进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 16);
			cout << "n16进制数为：" << x << endl;
		}
		else menu();
	}
}
void two_menu_3()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）10进制数  --->  2进制数";
		cout << "n（2）10进制数  --->  8进制数";
		cout << "n（3）10进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}
void two_menu_4()
{
	int n = -1;
	string x;
	while (n != 0) {
		cout << "n*******************************";
		cout << "n（1）16进制数  --->  2进制数";
		cout << "n（2）16进制数  --->  8进制数";
		cout << "n（3）16进制数  --->  10进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			cout << "n10进制数为：" << x;
		}
		else menu();
	}
}

非法性判断

注意小数点的个数，不符合进制要求的数字或字符。
n为进制，x为输入的进制数，sign为正负，point为小数点个数。（可以用do while进行化简）

复制代码

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int legal(int n, string& x,int sign)
{
	unsigned int point = 0, illegal = 0,i;
	if (x[0] == '-')
		sign++;
	for (i = 0 + sign; i < x.length(); i++)
	{
		if (x[i] == '.')
		{
			point++;
			continue;
		}
		if (x[i] < '0' || x[i] >= n + '0')
			illegal++;
		if(n==16&&(x[i]>='A'||x[i]<='F'))
			continue;
	}
	while (point >= 2 || illegal > 0)
	{
		cout << "输入错误，请重新输入：";
		cin >> x;
		sign = 0;
		if (x[0] == '-')
			sign++;
		point = 0, illegal = 0;
		for (i = 0 + sign; i < x.size(); i++)
		{
			if (x[i] == '.')
			{
				point++;
				continue;
			}
			if (x[i] < '0' || x[i]>n + '0')
				illegal++;
			if (n == 16 && (x[i] >= 'A' || x[i] <= 'F'))
				continue;
		}
	}
	return point;
}

其他进制转换为十进制

复制代码

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void ndec(int  n, string& x)
{
	unsigned int whole_n = 0, i, j, k, point = 0, sign = 0, num = 1, whole = 0, small_n = 0, wn = 1, sn = 0, control_small = 0;//whole为整数部分，whole_n为整数位数（若为负数不会加一）
	double small = 0, new_num;
	if (x[0] == '-')
		sign++;
	point=legal(n, x, sign);
	if (point == 1)
	{
		for (i = 0 + sign; i < x.size(); i++, whole_n++)
			if (x[i] == '.')
				break;
		for (i = i + 1; i < x.size(); i++)
			small_n++;
		for (j = 0 + sign; j < whole_n + sign; j++)
		{
			num = 1;
			for (k = 0; k < whole_n + sign - j - 1; k++)
				num = num * n;
			if (x[j] >= 'A' && x[j] <= 'F')
				whole = whole + (int(x[j]) - 55) * num;
			else whole = whole + (int(x[j]) - 48) * num;
		}
		for (control_small = 0, j = j + 1; j < x.size(); j++)
		{
			if (control_small >= 6)
				break;
			num = 1;
			for (k = 0; k < j - whole_n - sign; k++)
				num = num * n;
			if (x[j] >= 'A' && x[j] <= 'F')
				small = small + (int(x[j]) - double(55)) / num;
			else small = small + (int(x[j]) - double(48)) / num;
			control_small++;
		}
	}
	else
	{
		for (i = 0 + sign; i < x.size(); i++)
			whole_n++;
		for (i = 0 + sign; i < x.size() + sign; i++)
		{
			num = 1;
			for (k = 0; k < x.size() - i - 1; k++)
				num = num * n;
			if (x[i] >= 'A' && x[i] <= 'F')
				whole = whole + (int(x[i]) - 55) * num;
			else whole = whole + (int(x[i]) - 48) * num;
		}
	}
	new_num = whole + small;
	double t = new_num;//以下是将数字转化为字符串
	x = "";
	if (sign)
		x += '-';
	while (int(t) / 10 != 0)
	{
		wn++;
		t = t / 10;
	}
	t = new_num;
	if (point)
	{
		while (t * 10 != (int(t)) * double(10))
		{
			sn++;
			t = t * 10;
		}
	}
	t = new_num;
	for (i = 0 + sign; i < wn + sign; i++)
	{
		num = 1;
		for (k = 0; k < wn + sign - i - 1; k++)
			num = num * 10;
		x += int(t / num) + '0';
		t = int(t) % num;
	}
	if (point)
	{
		x += '.';
		t = new_num;
		for (i = 0; i < sn; i++)
		{
			x += int((t - int(t)) * 10) + '0';
			t = t * 10;
		}
	}
}

十进制转换为其他进制

复制代码

void decn(string& x, int n)
{
	unsigned int whole_n = 0, small_n = 0, i, j, point = 0, sign = 0, whole = 0, control_small;
	double small = 0, new_num, t;
	if (x[0] == '-')
		sign++;
	point = legal(10, x, sign);
	for (i = 0 + sign; i < x.size(); i++)
	{
		if (x[i] == '.')
			break;
		whole *= 10;
		whole = whole + int(x[i] - '0');
	}
	for (j = x.size() - 1; j > i; j--)
	{
		small = small + x[j] - '0';
		small = small / 10;
	}
	new_num = whole + small;
	x = "";
	if (sign)
		x = "-";
	fun_1(whole, x, n);
	t = small;
	if (point)
	{
		x += '.';
		control_small = 0;
		while (control_small < 5 && int(t * n) != t * n)
		{
			if (t * n >= 10)
				x = x + char(int(t * n) + 55);
			else
				x = x + char(int(t * n) + 48);
			t = t * n - int(t * n);
			control_small++;
		}
		if (t * n >= 10)
			x = x + char(int(t * n) + 55);
		else
			x = x + char(int(t * n) + 48);
	}
}
void fun_1(int i, string& x, int n)
{
	if (i >= n)
	{
		fun_1(i / n, x, n);
		if (i >= 10)
			x = x + char(i % n + 55);
		else
			x = x + char(i % n + 48);
	}
	else
	{
		if (i >= 10)
			x = x + char(i + 55);
		else
			x = x + char(i + 48);
	}
}

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void decn(string& x, int n)
{
	unsigned int whole_n = 0, small_n = 0, i, j, point = 0, sign = 0, whole = 0, control_small;
	double small = 0, new_num, t;
	if (x[0] == '-')
		sign++;
	point = legal(10, x, sign);
	for (i = 0 + sign; i < x.size(); i++)
	{
		if (x[i] == '.')
			break;
		whole *= 10;
		whole = whole + int(x[i] - '0');
	}
	for (j = x.size() - 1; j > i; j--)
	{
		small = small + x[j] - '0';
		small = small / 10;
	}
	new_num = whole + small;
	x = "";
	if (sign)
		x = "-";
	fun_1(whole, x, n);
	t = small;
	if (point)
	{
		x += '.';
		control_small = 0;
		while (control_small < 5 && int(t * n) != t * n)
		{
			if (t * n >= 10)
				x = x + char(int(t * n) + 55);
			else
				x = x + char(int(t * n) + 48);
			t = t * n - int(t * n);
			control_small++;
		}
		if (t * n >= 10)
			x = x + char(int(t * n) + 55);
		else
			x = x + char(int(t * n) + 48);
	}
}
void fun_1(int i, string& x, int n)
{
	if (i >= n)
	{
		fun_1(i / n, x, n);
		if (i >= 10)
			x = x + char(i % n + 55);
		else
			x = x + char(i % n + 48);
	}
	else
	{
		if (i >= 10)
			x = x + char(i + 55);
		else
			x = x + char(i + 48);
	}
}

全部代码

复制代码

#include<string>
#include <iostream>
#include<iomanip>
using namespace std;
void menu();
void two_menu_1();
void two_menu_2();
void two_menu_3();
void two_menu_4();
void ndec(int, string&);
void decn(string&, int);
void fun_1(int, string&, int);
int legal(int, string&,int);

int main()
{
	menu();
	return 0;
}

void menu()
{
	int n = -1;
	while (n != 0)
	{
		cout << "n**********************";
		cout << "n（1）2进制数转换";
		cout << "n（2）8进制数转换";
		cout << "n（3）10进制数转换";
		cout << "n（4）16进制数转换";
		cout << "n（0）退出";
		cout << "n**********************";
		cout << "n请输入功能号：";
		cin >> n;
		while (n < 0 || n>4)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
			two_menu_1();
		else if (n == 2)
			two_menu_2();
		else if (n == 3)
			two_menu_3();
		else if (n == 4)
			two_menu_4();
		else return;
	}
}//主菜单的实现
void two_menu_1()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）2进制数  --->  8进制数";
		cout << "n（2）2进制数  --->  10进制数";
		cout << "n（3）2进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}//第一个子菜单
void two_menu_2()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）8进制数  --->  2进制数";
		cout << "n（2）8进制数  --->  10进制数";
		cout << "n（3）8进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 16);
			cout << "n16进制数为：" << x << endl;
		}
		else menu();
	}
}
void two_menu_3()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）10进制数  --->  2进制数";
		cout << "n（2）10进制数  --->  8进制数";
		cout << "n（3）10进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}
void two_menu_4()
{
	int n = -1;
	string x;
	while (n != 0) {
		cout << "n*******************************";
		cout << "n（1）16进制数  --->  2进制数";
		cout << "n（2）16进制数  --->  8进制数";
		cout << "n（3）16进制数  --->  10进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			cout << "n10进制数为：" << x;
		}
		else menu();
	}
}

void ndec(int  n, string& x)
{
	unsigned int whole_n = 0, i, j, k, point = 0, sign = 0, num = 1, whole = 0, small_n = 0, wn = 1, sn = 0, control_small = 0;//whole为整数部分，whole_n为整数位数（若为负数不会加一）
	double small = 0, new_num;
	if (x[0] == '-')
		sign++;
	point=legal(n, x, sign);
	if (point == 1)
	{
		for (i = 0 + sign; i < x.size(); i++, whole_n++)
			if (x[i] == '.')
				break;
		for (i = i + 1; i < x.size(); i++)
			small_n++;
		for (j = 0 + sign; j < whole_n + sign; j++)
		{
			num = 1;
			for (k = 0; k < whole_n + sign - j - 1; k++)
				num = num * n;
			if (x[j] >= 'A' && x[j] <= 'F')
				whole = whole + (int(x[j]) - 55) * num;
			else whole = whole + (int(x[j]) - 48) * num;
		}
		for (control_small = 0, j = j + 1; j < x.size(); j++)
		{
			if (control_small >= 6)
				break;
			num = 1;
			for (k = 0; k < j - whole_n - sign; k++)
				num = num * n;
			if (x[j] >= 'A' && x[j] <= 'F')
				small = small + (int(x[j]) - double(55)) / num;
			else small = small + (int(x[j]) - double(48)) / num;
			control_small++;
		}
	}
	else
	{
		for (i = 0 + sign; i < x.size(); i++)
			whole_n++;
		for (i = 0 + sign; i < x.size() + sign; i++)
		{
			num = 1;
			for (k = 0; k < x.size() - i - 1; k++)
				num = num * n;
			if (x[i] >= 'A' && x[i] <= 'F')
				whole = whole + (int(x[i]) - 55) * num;
			else whole = whole + (int(x[i]) - 48) * num;
		}
	}
	new_num = whole + small;
	double t = new_num;//以下是将数字转化为字符串
	x = "";
	if (sign)
		x += '-';
	while (int(t) / 10 != 0)
	{
		wn++;
		t = t / 10;
	}
	t = new_num;
	if (point)
	{
		while (t * 10 != (int(t)) * double(10))
		{
			sn++;
			t = t * 10;
		}
	}
	t = new_num;
	for (i = 0 + sign; i < wn + sign; i++)
	{
		num = 1;
		for (k = 0; k < wn + sign - i - 1; k++)
			num = num * 10;
		x += int(t / num) + '0';
		t = int(t) % num;
	}
	if (point)
	{
		x += '.';
		t = new_num;
		for (i = 0; i < sn; i++)
		{
			x += int((t - int(t)) * 10) + '0';
			t = t * 10;
		}
	}
}
void decn(string& x, int n)
{
	unsigned int whole_n = 0, small_n = 0, i, j, point = 0, sign = 0, whole = 0, control_small;
	double small = 0, new_num, t;
	if (x[0] == '-')
		sign++;
	point = legal(10, x, sign);
	for (i = 0 + sign; i < x.size(); i++)
	{
		if (x[i] == '.')
			break;
		whole *= 10;
		whole = whole + int(x[i] - '0');
	}
	for (j = x.size() - 1; j > i; j--)
	{
		small = small + x[j] - '0';
		small = small / 10;
	}
	new_num = whole + small;
	x = "";
	if (sign)
		x = "-";
	fun_1(whole, x, n);
	t = small;
	if (point)
	{
		x += '.';
		control_small = 0;
		while (control_small < 5 && int(t * n) != t * n)
		{
			if (t * n >= 10)
				x = x + char(int(t * n) + 55);
			else
				x = x + char(int(t * n) + 48);
			t = t * n - int(t * n);
			control_small++;
		}
		if (t * n >= 10)
			x = x + char(int(t * n) + 55);
		else
			x = x + char(int(t * n) + 48);
	}
}

void fun_1(int i, string& x, int n)
{
	if (i >= n)
	{
		fun_1(i / n, x, n);
		if (i >= 10)
			x = x + char(i % n + 55);
		else
			x = x + char(i % n + 48);
	}
	else
	{
		if (i >= 10)
			x = x + char(i + 55);
		else
			x = x + char(i + 48);
	}
}
int legal(int n, string& x,int sign)
{
	unsigned int point = 0, illegal = 0,i;
	if (x[0] == '-')
		sign++;
	for (i = 0 + sign; i < x.length(); i++)
	{
		if (x[i] == '.')
		{
			point++;
			continue;
		}
		if (x[i] < '0' || x[i] >= n + '0')
			illegal++;
		if(n==16&&(x[i]>='A'||x[i]<='F'))
			continue;
	}
	while (point >= 2 || illegal > 0)
	{
		cout << "输入错误，请重新输入：";
		cin >> x;
		sign = 0;
		if (x[0] == '-')
			sign++;
		point = 0, illegal = 0;
		for (i = 0 + sign; i < x.size(); i++)
		{
			if (x[i] == '.')
			{
				point++;
				continue;
			}
			if (x[i] < '0' || x[i]>n + '0')
				illegal++;
			if (n == 16 && (x[i] >= 'A' || x[i] <= 'F'))
				continue;
		}
	}
	return point;
}

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#include<string>
#include <iostream>
#include<iomanip>
using namespace std;
void menu();
void two_menu_1();
void two_menu_2();
void two_menu_3();
void two_menu_4();
void ndec(int, string&);
void decn(string&, int);
void fun_1(int, string&, int);
int legal(int, string&,int);


int main()
{
	menu();
	return 0;
}


void menu()
{
	int n = -1;
	while (n != 0)
	{
		cout << "n**********************";
		cout << "n（1）2进制数转换";
		cout << "n（2）8进制数转换";
		cout << "n（3）10进制数转换";
		cout << "n（4）16进制数转换";
		cout << "n（0）退出";
		cout << "n**********************";
		cout << "n请输入功能号：";
		cin >> n;
		while (n < 0 || n>4)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
			two_menu_1();
		else if (n == 2)
			two_menu_2();
		else if (n == 3)
			two_menu_3();
		else if (n == 4)
			two_menu_4();
		else return;
	}
}//主菜单的实现
void two_menu_1()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）2进制数  --->  8进制数";
		cout << "n（2）2进制数  --->  10进制数";
		cout << "n（3）2进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入2进制数：";
			cin >> x;
			ndec(2, x);
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}//第一个子菜单
void two_menu_2()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）8进制数  --->  2进制数";
		cout << "n（2）8进制数  --->  10进制数";
		cout << "n（3）8进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			cout << "n10进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "请输入8进制数：";
			cin >> x;
			ndec(8, x);
			decn(x, 16);
			cout << "n16进制数为：" << x << endl;
		}
		else menu();
	}
}
void two_menu_3()
{
	int n = -1;
	string x;
	while (n != 0)
	{
		cout << "n*******************************";
		cout << "n（1）10进制数  --->  2进制数";
		cout << "n（2）10进制数  --->  8进制数";
		cout << "n（3）10进制数  --->  16进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入10进制数：";
			cin >> x;
			decn(x, 16);
			cout << "n16进制数为：" << x;
		}
		else menu();
	}
}
void two_menu_4()
{
	int n = -1;
	string x;
	while (n != 0) {
		cout << "n*******************************";
		cout << "n（1）16进制数  --->  2进制数";
		cout << "n（2）16进制数  --->  8进制数";
		cout << "n（3）16进制数  --->  10进制数";
		cout << "n（0）返回上级目录";
		cout << "n*******************************";
		cout << "n请输入功能号:";
		cin >> n;
		while (n < 0 || n>3)
		{
			cout << "n输入错误，请重新输入功能号：";
			cin >> n;
		}
		if (n == 1)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 2);
			cout << "n2进制数为：" << x;
		}
		else if (n == 2)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			decn(x, 8);
			cout << "n8进制数为：" << x;
		}
		else if (n == 3)
		{
			cout << "n请输入16进制数：";
			cin >> x;
			ndec(16, x);
			cout << "n10进制数为：" << x;
		}
		else menu();
	}
}

void ndec(int  n, string& x)
{
	unsigned int whole_n = 0, i, j, k, point = 0, sign = 0, num = 1, whole = 0, small_n = 0, wn = 1, sn = 0, control_small = 0;//whole为整数部分，whole_n为整数位数（若为负数不会加一）
	double small = 0, new_num;
	if (x[0] == '-')
		sign++;
	point=legal(n, x, sign);
	if (point == 1)
	{
		for (i = 0 + sign; i < x.size(); i++, whole_n++)
			if (x[i] == '.')
				break;
		for (i = i + 1; i < x.size(); i++)
			small_n++;
		for (j = 0 + sign; j < whole_n + sign; j++)
		{
			num = 1;
			for (k = 0; k < whole_n + sign - j - 1; k++)
				num = num * n;
			if (x[j] >= 'A' && x[j] <= 'F')
				whole = whole + (int(x[j]) - 55) * num;
			else whole = whole + (int(x[j]) - 48) * num;
		}
		for (control_small = 0, j = j + 1; j < x.size(); j++)
		{
			if (control_small >= 6)
				break;
			num = 1;
			for (k = 0; k < j - whole_n - sign; k++)
				num = num * n;
			if (x[j] >= 'A' && x[j] <= 'F')
				small = small + (int(x[j]) - double(55)) / num;
			else small = small + (int(x[j]) - double(48)) / num;
			control_small++;
		}
	}
	else
	{
		for (i = 0 + sign; i < x.size(); i++)
			whole_n++;
		for (i = 0 + sign; i < x.size() + sign; i++)
		{
			num = 1;
			for (k = 0; k < x.size() - i - 1; k++)
				num = num * n;
			if (x[i] >= 'A' && x[i] <= 'F')
				whole = whole + (int(x[i]) - 55) * num;
			else whole = whole + (int(x[i]) - 48) * num;
		}
	}
	new_num = whole + small;
	double t = new_num;//以下是将数字转化为字符串
	x = "";
	if (sign)
		x += '-';
	while (int(t) / 10 != 0)
	{
		wn++;
		t = t / 10;
	}
	t = new_num;
	if (point)
	{
		while (t * 10 != (int(t)) * double(10))
		{
			sn++;
			t = t * 10;
		}
	}
	t = new_num;
	for (i = 0 + sign; i < wn + sign; i++)
	{
		num = 1;
		for (k = 0; k < wn + sign - i - 1; k++)
			num = num * 10;
		x += int(t / num) + '0';
		t = int(t) % num;
	}
	if (point)
	{
		x += '.';
		t = new_num;
		for (i = 0; i < sn; i++)
		{
			x += int((t - int(t)) * 10) + '0';
			t = t * 10;
		}
	}
}
void decn(string& x, int n)
{
	unsigned int whole_n = 0, small_n = 0, i, j, point = 0, sign = 0, whole = 0, control_small;
	double small = 0, new_num, t;
	if (x[0] == '-')
		sign++;
	point = legal(10, x, sign);
	for (i = 0 + sign; i < x.size(); i++)
	{
		if (x[i] == '.')
			break;
		whole *= 10;
		whole = whole + int(x[i] - '0');
	}
	for (j = x.size() - 1; j > i; j--)
	{
		small = small + x[j] - '0';
		small = small / 10;
	}
	new_num = whole + small;
	x = "";
	if (sign)
		x = "-";
	fun_1(whole, x, n);
	t = small;
	if (point)
	{
		x += '.';
		control_small = 0;
		while (control_small < 5 && int(t * n) != t * n)
		{
			if (t * n >= 10)
				x = x + char(int(t * n) + 55);
			else
				x = x + char(int(t * n) + 48);
			t = t * n - int(t * n);
			control_small++;
		}
		if (t * n >= 10)
			x = x + char(int(t * n) + 55);
		else
			x = x + char(int(t * n) + 48);
	}
}

void fun_1(int i, string& x, int n)
{
	if (i >= n)
	{
		fun_1(i / n, x, n);
		if (i >= 10)
			x = x + char(i % n + 55);
		else
			x = x + char(i % n + 48);
	}
	else
	{
		if (i >= 10)
			x = x + char(i + 55);
		else
			x = x + char(i + 48);
	}
}
int legal(int n, string& x,int sign)
{
	unsigned int point = 0, illegal = 0,i;
	if (x[0] == '-')
		sign++;
	for (i = 0 + sign; i < x.length(); i++)
	{
		if (x[i] == '.')
		{
			point++;
			continue;
		}
		if (x[i] < '0' || x[i] >= n + '0')
			illegal++;
		if(n==16&&(x[i]>='A'||x[i]<='F'))
			continue;
	}
	while (point >= 2 || illegal > 0)
	{
		cout << "输入错误，请重新输入：";
		cin >> x;
		sign = 0;
		if (x[0] == '-')
			sign++;
		point = 0, illegal = 0;
		for (i = 0 + sign; i < x.size(); i++)
		{
			if (x[i] == '.')
			{
				point++;
				continue;
			}
			if (x[i] < '0' || x[i]>n + '0')
				illegal++;
			if (n == 16 && (x[i] >= 'A' || x[i] <= 'F'))
				continue;
		}
	}
	return point;
}