数制转换

/*******************

    Base Transform
        
*******************/
#include <iostream>
#include <cstring>
#include <string>

using namespace std;

string str;
int start[1000],ans[1000],res[1000];//被除数,商,余数

//转换前后的进制
int oldBase,newBase;

int change()
{//各个数位还原为数字形式
    int len=str.length();
    start[0]=len;
    for(int i=0;i<=len;i++)
    {
        if(str[i] >= '0' && str[i] <= '9')
        {
            start[i+1] = str[i] - '0';
            if(start[i+1]>=oldBase)
            {
                cout<<"input error!"<<endl;
                return -1;
            }
        }
        if(str[i] >= 'a' && str[i] <= 'f')
        {
            start[i+1] = str[i] - 'a' + 10;
            if(start[i+1]>=oldBase)
            {
                cout<<"input error!"<<endl;
                return -1;
            }
        }
        if(str[i] >= 'A' && str[i] <= 'F')
        {//大小写同时支持
            start[i+1] = str[i] - 'A' + 10;
            if(start[i+1]>=oldBase)
            {
                cout<<"input error!"<<endl;
                return -1;
            }
        }
    }
    return 1;
}

void solve()
{
    memset(res,0,sizeof(res));//余数初始化为空
    int y,i,j;

    while(start[0] >= 1)//
    {
        y=0;
        i=1;
        ans[0]=start[0];
        
        while(i<=start[0])
        {
            y=y*oldBase+start[i];
            ans[i++]=y/newBase;
            y%=newBase;
        }
        res[++res[0]] = y;//这一轮运算得到的余数
        i = 1;
        //找到下一轮商的起始处
        while((i<=ans[0]) && (ans[i]==0)) i++;
        //清除这一轮使用的被除数
        memset(start,0,sizeof(start));
        //本轮得到的商变为下一轮的被除数
        for(j = i;j <= ans[0];j++)
            start[++start[0]] = ans[j]; 
        memset(ans,0,sizeof(ans)); 
        //清除这一轮的商，为下一轮运算做准备
    }
}

void output()
{//从高位到低位逆序输出
    int i;
    cout<<"output:";
    for(i = res[0];i >= 1;--i)
    {  
        if(res[i]>=10&&res[i]<=15)//输出为大写字母
            cout<<(char)(res[i]-10+'A');
        else
            cout<<res[i];
    }
    cout<<endl; 
}

int main(int argc, char *argv[]) {
    cout<<"conversion"<<endl;
    cout<<"oldBase:";
    cin>>oldBase;
    cout<<"newBase:";
    cin>>newBase;
    while(1)
    {
        cout<<"input:";
        cin>>str;
        if(change()==1)
        {
            solve();
            output();
            cout<<"'q' to quit,any other key to continue:";
            cin.get();
            if(cin.get()=='q')
                break;
        }
    }
    return 0;
}