高精度整数类

High-Precision(Integer).cpp

@@ -0,0 +1,189 @@
+#include <cstdio>
+#include <cstring>
+
+using namespace std;
+
+class lint
+{
+private:
+	int s_length, n_length, *num;
+	char *temp;
+	int max(int x, int y);
+	void clear();
+	int nextshort(int offset);
+	lint mul1(int x, int offset);
+
+public:
+	lint(int len);
+	void read();
+	void write();
+	lint operator + (lint x);
+	lint operator - (lint x);
+	lint operator * (lint x);
+	bool operator < (lint x);
+};
+
+int lint::max(int x, int y)
+{
+	return x > y ? x : y;
+}
+
+void lint::clear()
+{
+	memset(num, 0, n_length * sizeof(num[0]));
+}
+
+int lint::nextshort(int offset)
+{
+	int res = 0;
+	for (int i = max(offset - 3, 0); i <= offset; i++)
+	{
+		res = res * 10 + (temp[i] - '0');
+	}
+	return res;
+}
+
+lint lint::mul1(int x, int offset)
+{
+	lint res(s_length);
+	int d = 0;
+	for (int i = 0; i + offset < n_length; i++)
+	{
+		d = num[i] * x + d;
+		res.num[i + offset] = d % 10000;
+		d /= 10000;
+	}
+	return res;
+}
+
+lint::lint(int len)
+{
+	s_length = len;
+	n_length = len / 4;
+	temp = new char[s_length];
+	num = new int[n_length];
+	clear();
+}
+
+void lint::read()
+{
+	scanf("%s", temp);
+	clear();
+	int l = strlen(temp), k = 0;
+	for (int i = l - 1; i >= 0; i -= 4)
+	{
+		num[k++] = nextshort(i);
+	}
+}
+
+void lint::write()
+{
+	int i;
+	for (i = n_length - 1; i >= 0; i--)
+	{
+		if (num[i] != 0)
+		{
+			break;
+		}
+	}
+	if (i == -1)
+	{
+		printf("0");
+		return;
+	}
+	printf("%d", num[i]);
+	for (i--; i >= 0; i--)
+	{
+		printf("%04d", num[i]);
+	}
+}
+
+lint lint::operator + (lint x)
+{
+	lint res(s_length);
+	int d = 0;
+	for (int i = 0; i < n_length; i++)
+	{
+		d += num[i] + x.num[i];
+		res.num[i] = d % 10000;
+		d /= 10000;
+	}
+	return res;
+}
+
+lint lint::operator - (lint x)
+{
+	lint res(s_length);
+	int d = 0;
+	for (int i = 0; i < n_length; i++)
+	{
+		d += num[i] - x.num[i];
+		res.num[i] = (d + 10000) % 10000;
+		d = d < 0 ? -1 : 0;
+	}
+	return res;
+}
+
+lint lint::operator * (lint x)
+{
+	lint res(s_length), t(s_length);
+	for (int i = 0; i < s_length; i++)
+	{
+		t = mul1(x.num[i], i);
+		res = res + t;
+	}
+	return res;
+}
+
+bool lint::operator < (lint x)
+{
+	for (int i = n_length - 1; i >= 0; i--)
+	{
+		if (num[i] < x.num[i])
+		{
+			return true;
+		}
+		else if (num[i] > x.num[i])
+		{
+			return false;
+		}
+	}
+	return false;
+}
+
+int main()
+{
+	lint a(100), b(100);
+	char op[10];
+	while (true)
+	{
+		a.read();
+		scanf("%s", op);
+		b.read();
+		switch (op[0])
+		{
+		case '+':
+			(a + b).write();
+			break;
+		case '-':
+			if (a < b)
+			{
+				printf("-");
+				(b - a).write();
+			}
+			else
+			{
+				(a - b).write();
+			}
+			break;
+		case '*':
+			(a * b).write();
+			break;
+		default:
+			printf("Invalid operator.");
+			break;
+		}
+		printf("\n");
+	}
+	return 0;
+}