> [code]#include <cstdio>
> #include <cstdlib>
> #include <cstring>
> using namespace std;
> 
> class BigFloat {
> public:
> 	static const int max_bit = 250;
> 	int size;
> 	int fracLen;
> 	int exp;
> 	long long val;
> 	long long bit[max_bit];
> public:
> 	BigFloat() {}
> 	BigFloat(char source[]) {
> 		memset(bit, 0, sizeof(bit));
> 		if (strchr(source, '.')) {
> 			for (char *rear = source + strlen(source) - 1; !*rear; --rear)
> 				;
> 			size_t len = strlen(source);
> 			fracLen = len - (strchr(source, '.') - source + 1);
> 			for (char *tmp = strchr(source, '.'); *tmp; ++tmp) {
> 				*tmp = *(tmp + 1);
> 			}
> 		} else
> 			fracLen = 0;
> 		val = atoi(source);
> 		bit[0] = val;
> 		size = 1;
> 	}
> 
> 	void multiBy(int val);
> 	void expBy(int e);
> 	void print();
> };
> 
> void BigFloat::multiBy(int val) {
> 	for (int i = 0; i < size; ++i)
> 		bit[i] *= val;
> 	for (int i = 0; i < size; ++i) {
> 		if (bit[i] > 9) {
> 			bit[i + 1] += bit[i] / 10;
> 			bit[i] %= 10;
> 		}
> 	}
> 	while (bit[size]) {
> 		bit[size + 1] += bit[size] / 10;
> 		bit[size] %= 10;
> 		++size;
> 	}
> }
> 
> void BigFloat::expBy(int e) {
> 	exp = e;
> 	for (int i = 0; i < e - 1; ++i)
> 		multiBy(val);
> }
> 
> void BigFloat::print() {
> 	if (size <= exp * fracLen) {
> 		printf(".");
> 		for (int i = 0; i < exp * fracLen - size; ++i)
> 			putchar('0');
> 		int end = 0;
> 		while (!bit[end])
> 			++end;
> 		for (int i = size - 1; i >= end; --i)
> 			printf("%d", bit[i]);
> 	} else {
> 		for (int i = size - 1; i >= exp * fracLen; --i)
> 			printf("%d", bit[i]);
> 		int end = 0;
> 		while (!bit[end] && end < exp * fracLen)
> 			++end;
> 		if (end < exp * fracLen) {
> 			putchar('.');
> 			for (int i = exp * fracLen - 1; i >= end; --i)
> 				printf("%d", bit[i]);
> 		}
> 	}
> }
> 
> int main() {
> 	char source[8];
> 	int exp;
> 	while (scanf("%s%d", source, &exp) != EOF) {
> 		BigFloat bf(source);
> 		if (bf.val == 0) {
> 			printf("0\n");
> 			continue;
> 		}
> 		bf.expBy(exp);
> 		bf.print();
> 		putchar('\n');
> 	}
> 	return 0;
> }
> //另外, 下面是AC掉的Java code, 个人感觉上面那个C++的code不可能是格式的问题, 因为下面这个Java code AC掉了
> import java.io.*;
> import java.util.*;
> import java.math.*;
> 
> public class Main {
> 
> 	public static void main(String args[]) throws Exception {
> 		Scanner sin = new Scanner(System.in);
> 		while (sin.hasNext()) {
> 			BigDecimal bd = sin.nextBigDecimal();
> 			int n = sin.nextInt();
> 			String ans = bd.pow(n).stripTrailingZeros().toPlainString();
> 			if (ans.charAt(0) == '0')
> 				System.out.println(ans.substring(1));
> 			else
> 				System.out.println(ans);
> 		}
> 	}
> 
> }[/code]

我试了 10.1 1
结果是 .101
正确应该是 10.1
肯定还有小问题

• Re:求一个1001的让下面的这个C++ code WA掉的数据... (177) X_ray 2007-07-15 23:42:10