//模擬計算機(jī)的運(yùn)算，先把10進(jìn)制轉(zhuǎn)換成2進(jìn)制，然后移位相加，最后轉(zhuǎn)變回10進(jìn)制。#include <stdio.h>#include <stdlib.h>#include <string.h>//char *str_a = "111111111111111";char *str_a = "3";//char *str_b = "123456789012345";char *str_b = "1025";//先把10進(jìn)制轉(zhuǎn)換成2進(jìn)制int tran_bin (char *str, char **res, int *aim_len){	if ((str == NULL) || (res == NULL) || (aim_len == NULL))	{		printf ("%s.%d\n", __FILE__, __LINE__);		exit (1);	}	int str_len = strlen (str);	char *tmp = (char *)malloc (str_len + 1);	memcpy (tmp, str, str_len);	tmp[str_len] = '\0';	int res_len = str_len * 4  + 4;	*res = (char *)malloc (res_len + 1);	memset (*res, '0', res_len + 1);	(*res)[res_len] = '\0';	int dig = 0;	int len = str_len;	int value;	int res_index = 0;	int i;	while (len != 0)	{		dig = 0;		for (i = str_len - len; i < str_len; i++)		{			value = tmp[i] - '0' + dig * 10;			tmp[i] = value / 2 + '0';			dig = value % 2;		}		(*res)[res_index++] = dig + '0';		if (tmp[str_len - len] == '0')			len--;	}	*aim_len = res_index;	for (i = 0; i <= (res_index - 1) / 2; i++)	{		char ch = (*res)[i];		(*res)[i] = (*res)[res_index - 1 - i];		(*res)[res_index - 1 - i] = ch;	}	for (i =0; i < 80; i++)		printf ("%d", i % 10);	printf ("\n");	printf ("res= %s\n", *res);	printf ("res_index= %d\n", res_index);	return 0;}//移位相加int mul_bin (char **dst, int dst_len,  char **src, int src_len, char **aim){	if ((dst == NULL) || (src == NULL) || (aim == NULL))	{		printf ("%s.%d\n", __FILE__, __LINE__);		exit (1);	}	int res_len = ((dst_len + src_len + 1) / 4) * 4 + 4;	char *res = (char *)malloc (res_len + 1);	memset (res, '0', res_len);	res[res_len] = '\0';	int i;	int j;	int k;	for (i = 0; i < src_len; i++)	{		if ((*src)[i] == '1')		{			int acc = 0;			int value;			for (j = dst_len - 1, k = res_len - (src_len - i); j >= 0; j--, k--)			{				value = res[k] - '0' + (*dst)[j] - '0' + acc;				res[k] = value % 2 + '0';				acc = value / 2;					}			while (acc == 1)			{				value = res[k] - '0' + acc;				res[k] = value % 2 + '0';				acc = value / 2;				k--;			}		}	}	*aim = res;	printf ("%s\n", res);	printf ("aim_len= %d\n", res_len);		return 0;}//轉(zhuǎn)變回10進(jìn)制int tran_dec (char *aim, char **dec_res){	int len = strlen (aim);	*dec_res = (char *)malloc (len + 1);	if (*dec_res == NULL)	{		printf ("%s.%d\n", __FILE__, __LINE__);		exit (1);	}	memset (*dec_res, '0', len);	(*dec_res)[len] = '\0';		int stand_step = 0;	char *stand_exp = (char *)malloc (len + 1);	if (stand_exp == NULL)	{		printf ("%s.%d\n", __FILE__, __LINE__);		exit (1);	}	memset (stand_exp, '0', len);	stand_exp[len] = '\0';	stand_exp[len - 1] = '1';	int i;	int j;	int acc;	int value;	for (i = len - 1; i >= 0; i--)	{		if (aim[i] == '1')		{			acc = 0;			for (j = len - 1; j >= 0; j--)			{				value = (*dec_res)[j] - '0' + stand_exp[j] - '0' + acc;				(*dec_res)[j] = value % 10 + '0';				acc = value / 10;			}			}		// 2 multiple of stand_exp		acc = 0;		for (j = len - 1; j >= 0; j--)		{			value = (stand_exp[j] - '0') * 2 + acc;			stand_exp[j] = value % 10 + '0';		   	acc = value / 10;		}	}		return 0;}int main (int argc, char **argv){	char *res_a;	char *res_b;	int len_a;	int len_b;	//tran_bin (str_a, &res_a, &len_a);	tran_bin (argv[1], &res_a, &len_a);	//tran_bin (str_b, &res_b, &len_b);	tran_bin (argv[2], &res_b, &len_b);	char *aim;	mul_bin (&res_a, len_a, &res_b, len_b, &aim);	char *dec_res;	tran_dec (aim, &dec_res);	int i = 0;	while (dec_res[i] == '0')		i++;	printf ("%s\n", dec_res + i);	printf ("len= %d\n", strlen (dec_res + i));		return 0;}