斐波那契数列大数加法

昨天做完n!的大数实现，再看变形的大数加法(fibonacci)实现，感觉好多了.

空间估算经验公式

size_t fnCalcFibonacciArySize(size_t n) {    /// 从资料上看到的经验公式    return (size_t)(n / 4 + 4);}

实现

/// @file \exam_fibonacci\main.cpp/// @brief 斐波那契数列大数加法///     ary[0] = 1, ary[1] = 1; ary[2] = ary[0] + ary[1], ary[n] = ary[n-1] + ary[n-2]///     大数数组的估算 ary[n/4 + 4]#include <stdlib.h>#include <stdio.h>#include <string.h>#include <conio.h>#ifndef WORD#define WORD unsigned short#endifvoid fnCalcFibonacci(); ///< 计算斐波那契数列n的大数size_t fnCalcFibonacciArySize(size_t n); ///< 估算斐波那契数列n时的大数数组sizevoid fnCalcFibonacci(WORD* pAryAdd1, WORD* pAryAdd2, WORD* pArySum, size_t nArySize);void fnPrintFibonacci(WORD* pArySum, size_t nArySize);int main(int argc, char* argv[]) {    do     {        fnCalcFibonacci();        printf("press 'c' to continue, other key to quit\n");        if ('c' != _getch())            break;    } while (1);    /// 和其它人实现的fibonacci大数加法结果比对过, 正确^_^    /** run result    please input fibonacci's n:0        press 'c' to continue, other key to quit    please input fibonacci's n:1      press 'c' to continue, other key to quit    please input fibonacci's n:2    2    press 'c' to continue, other key to quit    please input fibonacci's n:100    573147844013817084101    press 'c' to continue, other key to quit    please input fibonacci's n:200    453973694165307953197296969697410619233826    press 'c' to continue, other key to quit    please input fibonacci's n:1000    70330367711422815821835254877183549770181269836358732742604905087154537118196933    57974224949456261173348775044924176599108818636326545022364710601205337412127386    7339111198139373125598767690091902245245323403501    press 'c' to continue, other key to quit    */    return 0;}void fnCalcFibonacci() {    size_t n = 0;    size_t nArySize = 0;    size_t nIndex = 0;    WORD* pAry1 = NULL;    WORD* pAry2 = NULL;    WORD* pAry3 = NULL;    WORD* pAryAdd1 = NULL;    WORD* pAryAdd2 = NULL;    WORD* pArySum = NULL;    WORD* pAryTmp = NULL;    printf("please input fibonacci's n:");    fflush(stdin); ///< 清空输入缓冲区    scanf("%u", &n);    nArySize = fnCalcFibonacciArySize(n);    /// 算出需要开配的WORD数组大小    nArySize = (nArySize - (nArySize % sizeof(WORD))) / sizeof(WORD) + 1;    /// 开辟资源    pAry1 = (WORD*)malloc(nArySize * sizeof(WORD));    if (NULL != pAry1) {        memset(pAry1, 0, nArySize * sizeof(WORD));        pAry1[nArySize - 1] = 1;    }    pAry2 = (WORD*)malloc(nArySize * sizeof(WORD));    if (NULL != pAry2) {        memset(pAry2, 0, nArySize * sizeof(WORD));        pAry2[nArySize - 1] = 1;    }    pAry3 = (WORD*)malloc(nArySize * sizeof(WORD));    if (NULL != pAry3) {        memset(pAry3, 0, nArySize * sizeof(WORD));    }        /// 计算Fibonacci大数数列    if ((NULL != pAry1) && (NULL != pAry2) && (NULL != pAry3)) {        pAryAdd1 = pAry1;        pAryAdd2 = pAry2;        pArySum = pAry3;        for (nIndex = 2; nIndex <= n; nIndex++) {            fnCalcFibonacci(pAryAdd1, pAryAdd2, pArySum, nArySize);            /// 如果不是最后一次加法, 重新设置数组(被加数，加数，和)            if (nIndex != n) {                pAryTmp = pAryAdd1;                pAryAdd1 = pAryAdd2;                pAryAdd2 = pArySum;                pArySum = pAryTmp;            }        }        /// 打印结果        fnPrintFibonacci(pArySum, nArySize);    }    /// 释放资源    if (NULL != pAry1) {        free(pAry1);        pAry1 = NULL;    }    if (NULL != pAry2) {        free(pAry2);        pAry2 = NULL;    }    if (NULL != pAry3) {        free(pAry3);        pAry3 = NULL;    }}void fnCalcFibonacci(WORD* pAryAdd1, WORD* pAryAdd2, WORD* pArySum, size_t nArySize) {    size_t nIndex = 0;    size_t nPos = nArySize - 1;    int iSum = 0;    int iCarry = 0;    memset(pArySum, 0, sizeof(WORD) * nArySize); ///< ! sizeof(WORD)    /// 为了防止数组nPos越界操作, 循环的次数必须比数组size小2    for (nIndex = 0; nIndex < (nArySize - 1); nIndex++, nPos--) {        iSum = pAryAdd1[nPos] + pAryAdd2[nPos] + iCarry;        pArySum[nPos] = iSum % 10000;        iCarry = (iSum - iSum % 10000) / 10000;    }}void fnPrintFibonacci(WORD* pArySum, size_t nArySize) {    bool bFirstShow = true;    size_t nIndex = 0;    for (nIndex = 0; nIndex < nArySize; nIndex++) {        if (bFirstShow) {            /// 找到第一个不为零的数据            if (0 == pArySum[nIndex])                continue;            bFirstShow = false;            printf("%d", pArySum[nIndex]);        }        else {            printf("%4.4d", pArySum[nIndex]);        }    }    printf("\n");}size_t fnCalcFibonacciArySize(size_t n) {    /// 从资料上看到的经验公式    return (size_t)(n / 4 + 4);}