编写一个进制转换器

#include<iostream>
#include<stdlib.h>
#include<cmath>
using namespace std;

void BtoD(int B, int &D, int &W)//二转十
{
int bit;
if (B > 0)
{
bit = B % 10;
D = D + bit*(int)(pow(2, float(W)));//取余，最低位是否是1
B = B / 10;
W++;//去掉最低位
BtoD(B, D, W);//二进制码每一位对应权重加1

}
}
void main()
{
char bi[255];//二进制数内存
int input;//输出进制数
char type;//输出进制类型
char contin;//标志是否继续进行
int de = 0;//十进制数
int weight = 0;//二进制码最低位权重
do
{
cout << "请选择输入数的进制类型" << endl;
cout << "B-二进制   O-八进制   D-十进制     H-十六进制" << endl;
cout << "选择进制为: ";
cin >> type;
switch (type)
{
case 'B':
cout << "输入的二进制数: ";//二转为十进制
cin >> input;
BtoD(input, de, weight);
cout << "其八进制数是:" << oct << de << endl;
cout << "其十进制数是:" << dec << de << endl;
cout << "其十六进制是:" << hex << de << endl;
break;
case'O':
cout << "输入的八进制数: ";//八进制转换为二进制
cin >> oct >> input;
cout << "其二进制数是: ";
itoa(input, bi, 2);
cout << bi << endl;
cout << "其十进制数是:" << dec << input << endl;
cout << "其十六进制数是:" << hex << input << endl;
break;
case'D':
cout << "输入的十进制数: ";//十进制转换为二进制
cin >> dec >> input;
cout << "其二进制数是: ";
itoa(input, bi, 2);
cout << "其八进制数是: " << oct << input << endl;
cout << "其十六进制数是: " << hex << input << endl;
break;
case'H':
cout << "输入的十六进制数: ";//十六进制转换为二进制
cin >> hex >> input;
cout << "其二进制数是: ";
itoa(input, bi, 2);
cout << bi << endl;
cout << "其八进制数是: " << oct << input << endl;
cout << "其十进制数是: " << dec << input << endl;
break;
default:
cout << "选择进制类型错误\n";
exit(-1);

}
cout << "是否继续进行转换？  Y-是，N-否" << endl;
cin >> contin;
} while (contin == 'Y');
}