大数相乘

任意位数计算的高效算法实现

最新推荐文章于 2024-01-20 09:00:00 发布

原创最新推荐文章于 2024-01-20 09:00:00 发布 · 423 阅读

0 ·

CC 4.0 BY-SA版权

改变 op1 和 op2 可以实现任意位数的计算，代码如下：

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

void calc(char *op1,char *op2)
{
	int i;
	int j;
	int k = 0;
	int re;
	int carry = 0;
	int op1_len = strlen(op1);         //5
	int op2_len = strlen(op2);			//5	
	char *result = (char *)malloc(op1_len + op2_len + 1);
	for(i = 0;i <= op1_len + op2_len;i++)
		result[i] = 0;
	for(i = op1_len - 1;i >= 0;i--)
	{
		for(carry = 0,j = op2_len - 1;j >= 0;j--)
		{
			re = (op1[i] - '0') * (op2[j] - '0') + result[i + j + 1] + carry;
			result[i + j + 1] = (char)(re % 10);
			carry = (char)(re / 10);
		}
//		for(i = 0;i < op1_len + op2_len;i++)
//			printf("%d",result[i]);
//		printf("\n");
		result[i] = (char)carry;
	}
	for(i = 0;result[i] == 0 && i < op1_len + op2_len;i++)
		;
	for(;i < op1_len + op2_len;i++)
		printf("%d",result[i]);
}

int main()
{
	char *op1 = "1234567891011121314151617181920";
	char *op2 = "2019181716151413121110987654321";
	//char *op1 = "10000";
	//char *op2 = "10000";
	char *op3 = "12345";
	//  152399025
	//char *op1 = "99999";
	//char *op2 = "99999";
	// 9999800001
	char *op4 = "54321";
	// 2950771041
	calc(op1,op2);
	return 0;
}