add

public/c/ch2/bigcheng/bigchengnew.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+// 递归计算大整数乘积
+double bigdataride(long x, long y, int n) {
+    x = llabs(x);    y = llabs(y);
+    if (n == 1) {
+        return (double)x * y; // 基本情况
+    } else {
+        if (n % 2 == 1) n--; // 处理奇数位
+        long halfPow = (long)pow(10, n / 2);
+        long a = x / halfPow;
+        long b = x % halfPow;
+        long c = y / halfPow;
+        long d = y % halfPow;
+
+        // 递归计算
+        double ac = bigdataride(a, c, n / 2);
+        double bd = bigdataride(b, d, n / 2);
+        long aJb = a + b;
+        long cJd = c + d;
+        double abcd = bigdataride(aJb, cJd, n / 2);
+        // 返回最终结果
+        return ac * pow(10, n) + (abcd - ac - bd) * pow(10, n / 2) + bd;
+    }
+}
+
+int main() {
+    long x = 8782346786879887887L;
+    long y = 4524387689998798768L;
+    // 计算数字长度
+    char sx[20];
+    snprintf(sx, sizeof(sx), "%ld", x);
+    int n = strlen(sx);
+    // 计算并输出结果
+    double s = bigdataride(x, y, n);
+    printf("大数相乘的计算结果为：%lf\n", s);
+
+    return 0;
+}

public/c/ch2/bigcheng/bigchengold.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <string.h>
+#define MAX_LEN 1000
+// 计算两个大整数的乘积
+void multiply(const char* a, const char* b, char* result) {
+    int lenA = strlen(a), lenB = strlen(b), lenResult = lenA + lenB;
+    int arr[MAX_LEN * 2] = {0};
+
+    // 进行乘法运算
+    for (int i = 0; i < lenA; ++i)
+        for (int j = 0; j < lenB; ++j)
+            arr[i + j] += (a[lenA - i - 1] - '0') * (b[lenB - j - 1] - '0');
+    // 处理进位
+    for (int i = 0; i < lenResult - 1; ++i) {
+        arr[i + 1] += arr[i] / 10;
+        arr[i] %= 10;
+    }    
+    // 构建结果字符串
+    int index = 0;
+    while (index < lenResult && arr[index] == 0) ++index;
+    if (index == lenResult) strcpy(result, "0");
+    else {
+        for (int i = index; i < lenResult; ++i)
+            result[i - index] = arr[lenResult - i - 1] + '0';
+        result[lenResult - index] = '\0';
+    }
+}
+
+int main() {
+    char a[MAX_LEN + 1], b[MAX_LEN + 1], result[MAX_LEN * 2 + 1];
+    printf("输入第一个大整数: ");
+    scanf("%s", a);
+    printf("输入第二个大整数: ");
+    scanf("%s", b);
+    multiply(a, b, result);
+    printf("结果: %s\n", result);
+    return 0;
+}