C++1001

// Exponentiation.cpp : Defines the entry point for the console application.
//

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAX_INTEGER 49
#define MAX_DECIMAL 101
const int zero[200] = { 0 };

class longnumber{
public:
int upperbound, lowerbound;
int integer[MAX_INTEGER];
int decimal[MAX_DECIMAL];
bool isinteger;

//构造函数
longnumber() : upperbound(0), lowerbound(0), isinteger(false)
{
memcpy(integer, zero, MAX_INTEGER*sizeof(int));
memcpy(decimal, zero, MAX_DECIMAL*sizeof(int));
}

~longnumber()
{
upperbound = 0;
lowerbound = 0;
isinteger = false;
memcpy(integer, zero, MAX_INTEGER*sizeof(int));
memcpy(decimal, zero, MAX_DECIMAL*sizeof(int));
}
void setDecimal(int i, int a){
this->decimal[i] = a;
}
void setInteger(int i, int a){
this->integer[i] = a;
}
void setUpperbound(){
int i;
for (i = MAX_INTEGER - 1; integer[i] == 0 && i >= 0; i--);
if (integer[i] != 0)
{
upperbound = i + 1;
}
else
{
upperbound = i;
}

}

void setLowerbound(){
int i;
for (i = MAX_DECIMAL - 1; decimal[i] == 0 && i>0; i--);
lowerbound = i;
}
int getUpperbound(){
return this->upperbound;
}

int getLowerbound(){
return this->lowerbound;
}

void isInteger(bool f){
isinteger = (lowerbound == 0);
}

//大数乘法
longnumber operator *(longnumber &rhs){
longnumber temp;        //存放结果
int i, j, tempres;       //tempres为临时相乘结果
for (i = -this->lowerbound; i <= this->upperbound; i++)
{
for (j = -rhs.lowerbound; j <= rhs.upperbound; j++)
{
tempres = *getpos(this, i) * *getpos(&rhs, j);
*getpos(&temp, i + j) += tempres % 10;
*getpos(&temp, i + j + 1) = *getpos(&temp, i + j + 1) + tempres / 10 + *getpos(&temp, i + j) / 10;
*getpos(&temp, i + j) %= 10;
*getpos(&temp, i + j + 2) += *getpos(&temp, i + j + 1) / 10;
*getpos(&temp, i + j + 1) %= 10;
}
}
temp.setUpperbound();
temp.setLowerbound();
return temp;
}

//a为10的幂位数，范围为(...3,2,1,0,-1,-2,-3...)，返回指向大数ln的整数部分integer[]、或小数部分decimal[]的int的指针
static int* getpos(longnumber *ln, int a){
int* p;

if (a >= 0){
p = ln->integer + a;
return p;
}
else
{
p = ln->decimal - a;
return p;
}
}

void out()
{
int i;
for (i = upperbound - 1; i >= 0; i--)
{
printf("%d", integer[i]);
}
if(lowerbound!=0)
printf(".");
for (i = 1; i <= lowerbound; i++)
{
printf("%d", decimal[i]);
}
putchar('\n');
}

private:

};

int main(int argc, char* argv[])
{
char input[5];
int i, j, n;
char* pChar;
longnumber a, res;
while (scanf("%s %d", input, &n) == 2)
{
char* pDot = strchr(input, '.');

for (i = 0, pChar = pDot - 1; pChar >= input; i++, pChar--){
a.setInteger(i, *pChar - 48);
};
a.setUpperbound();
for (j = 1, pChar = pDot + 1; pChar <= (input + strlen(input) - 1); j++, pChar++){
a.setDecimal(j, *pChar - 48);
}
a.setLowerbound();

res = a;

for (i = 1; i < n; i++){
res = res * a;
}
res.out();
a.~longnumber();
res.~longnumber();
}
return 0;
}