2020-4-27

Author: wangzhijie01

2020-4-27-大非负整数相乘/hugeint.c

@@ -0,0 +1,103 @@
+/*************************************************************************
+    > File Name: hugeint.c
+    > Author: wangzhijie
+    > Mail: [email protected] 
+    > Created Time: 2020年04月27日 星期一 11时06分14秒
+ ************************************************************************/
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define ARRSIZE	100
+
+unsigned char num1[ARRSIZE] = {
+	0
+};
+unsigned char num2[ARRSIZE] = {
+	0
+};
+
+
+int *hugesum(unsigned char *an1, unsigned char *an2)
+{
+	if(NULL == an1 || NULL == an2)
+		return NULL;
+
+	int *sum = malloc(sizeof(int) * 2 * ARRSIZE);
+	if(NULL == sum)
+		return NULL;
+	memset(sum, 0 , 2 * ARRSIZE * sizeof(int));
+
+	//计算出大整数的有效位
+	int validnum1 = 0, validnum2 = 0, i, j, power;
+	for(i = 0; i < ARRSIZE; i++){
+		if(an1[i] != 0xff){
+			validnum1++;	
+		}
+		if(an2[i] != 0xff){
+			validnum2++;
+		}
+		if(an1[i] == 0xff && an2[i] == 0xff)
+			break;
+	}
+	printf("validnum1=%d, validnum2=%d\n",validnum1,validnum2);
+	
+	//用乘数和被乘数每一位进行乘法运算
+	for(i = 0; i < validnum1; i++){
+		for(j = 0; j < validnum2; j++){
+			power = (int)pow(10, i+j);
+			sum[i+j] += an1[i] * an2[j];
+		}
+	}
+
+	//开始对sum进行进位
+	for(i = 0; i < (2 * ARRSIZE); i++){
+		if(sum[i] > 9){
+			sum[i + 1] += sum[i] / 10;
+			sum[i] = sum[i] % 10;
+		}
+	}
+
+	for(i = 2 * ARRSIZE - 1; i >= 0; i--){
+		if(sum[i] != 0)
+			break;
+	}
+	for(j = i; j >= 0; j--){
+		printf("%d",sum[j]);
+	}
+
+	printf("\n");
+	return sum;
+}
+
+int main()
+{
+	char buf[101] = {
+		0
+	};
+	memset(num1, 0xff, ARRSIZE);
+	memset(num2, 0xff, ARRSIZE);
+	int i, j;
+
+	while(scanf("%s", buf)){
+		if(num1[0] == 0xff){
+			int size = strlen(buf);
+			for(i = size - 1, j = 0; i >= 0; i--,j++){
+				num1[i] = buf[j] - 48;
+			}
+		}else if(num2[0] == 0xff){
+			int size = strlen(buf);
+			for(i = size - 1, j = 0; i >= 0; i--, j++){
+				num2[i] = buf[j] - 48;
+			}
+		}
+		memset(buf, 0, sizeof(buf));
+
+		if(num1[0] != 0xff && num2[0] != 0xff){
+			int *sum = hugesum(num1, num2);
+		}
+	}
+	
+	return 0;
+}

2020-4-27-大非负整数相乘/hugeint.study

@@ -0,0 +1,3 @@
+1:输入的buf位置顺序需要调换
+2:核心思想，需要对两个数每个位置相乘存储在sum中，然后对每个位置的数字进行进位，类似方法
+就是笔算乘法的做法