POJ1546 & HDU 1335 & ZOJ 1334 Basically Speaking（进制转换）

题目链接：

POJ：http://poj.org/problem?id=1546

HDU：http://acm.hdu.edu.cn/showproblem.php?pid=1335

ZOJ：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=334

Description

The Really Neato Calculator Company, Inc. has recently hired your team to help design their Super Neato Model I calculator. As a computer scientist you suggested to the company that it would be neato if this new calculator could convert among number bases.
The company thought this was a stupendous idea and has asked your team to come up with the prototype program for doing base conversion. The project manager of the Super Neato Model I calculator has informed you that the calculator will have the following neato
features:

It will have a 7-digital display.

Its buttons will include the capital letters A through F in addition to the digits 0 through 9.

It will support bases 2 through 16.

Input

The input for your prototype program will consist of one base conversion per line. There will be three numbers per line. The first number will be the number in the base you are converting from. The second number is the base you are converting from. The third
number is the base you are converting to. There will be one or more blanks surrounding (on either side of) the numbers. There are several lines of input and your program should continue to read until the end of file is reached.
Output

The output will only be the converted number as it would appear on the display of the calculator. The number should be right justified in the 7-digit display. If the number is to large to appear on the display, then print ``ERROR'' (without the quotes) right
justified in the display.
Sample Input

1111000  2 10
1111000  2 16
2102101  3 10
2102101  3 15
  12312  4  2
     1A 15  2
1234567 10 16
   ABCD 16 15

Sample Output

120
     78
   1765
    7CA
  ERROR
  11001
 12D687
   D071

Source

Mid-Central USA 1995

题意：

给出某一种进制的数，转换为另一种进制！

不管你认为它是不是很简单，反正我被坑了7个小时！


代码如下：

#include <cstdio>
#include <cstring>
#include <cmath>
char s[117], ans[117];
int a, b;
int k;
int len;
int check( char c)
{
    if(c == 'A')
        return 10;
    else if(c == 'B')
        return 11;
    else if(c == 'C')
        return 12;
    else if(c == 'D')
        return 13;
    else if(c == 'E')
        return 14;
    else if(c == 'F')
        return 15;
    else
        return c-'0';
}
char check1(int c)
{
    if(c == 10)
        return 'A';
    else if(c == 11)
        return 'B';
    else if(c == 12)
        return 'C';
    else if(c == 13)
        return 'D';
    else if(c == 14)
        return 'E';
    else if(c == 15)
        return 'F';
    else
        return c+'0';
}
int POW(int a, int len)
{
    int ss = 1;
    for(int i = 0; i < len; i++)
    {
        ss*=a;
    }
    return ss;
}

void slove()
{
    int r, tt = 0;
    for(int i = 0; i < len; i++)
    {
        tt += check(s[i])*pow(a*1.0,len-1-i);
    }
    //printf("tt:%d\n",tt);
    k = 0;
    while(tt)
    {
       r = tt%b;
        ans[k++] = check1(r);
        tt/=b;
    }
}

int main()
{
    while(scanf("%s",s)!=EOF)
    {
        len = strlen(s);
        scanf("%d %d",&a,&b);
        slove();
        if(k > 7)
        {
            printf("  ERROR\n");
            continue;
        }
        for(int i = 1; i <= 7-k; i++)
            printf(" ");
        for(int i = k-1; i >= 0; i--)
            printf("%c",ans[i]);
        printf("\n");
    }
    return 0;
}