uint.cpp

一个我的数据结构解题集合

#include <iostream>
#include <ctype.h>
#include "UInt.h"

using namespace std;


/* 构造函数: 通过字符串ch构造整数
 *           若字符串ch不代表无符号整数, 抛出std::invalid_argument
 */
UInt::UInt(const char *ch) {
	if (ch == 0)
		throw std::invalid_argument("UInt::UInt(const char *ch)\n"
									"\trequirement ch != 0 violated.\n");

	while (*ch != '\0' && isdigit(*ch)) {
		vec_.pushFront(Digit(*ch - '0'));		// 从char到Digit::Value的隐式转换
		++ch;
	}

	if (*ch != '\0')
		throw std::invalid_argument("UInt::UInt(const char *ch)\n"
									"\trequirement ch represents a number violated.\n");

} // UInt(const char *)


/* 本整数值加上rhs
 */
void UInt::add(const UInt& rhs) {
	Digit::Value carry = 0;							// 进位
	
	int ilhs = 0, irhs = 0;
	while ( ilhs < vec_.size() &&
			irhs < rhs.vec_.size() ) {

		vec_[ilhs].val += rhs.vec_[irhs].val + carry;
		carry = vec_[ilhs].trim();

		++ilhs;
		++irhs;
	}

	while ( irhs < rhs.vec_.size() ) {				// 加入剩余的位
		Digit d(rhs.vec_[irhs].val + carry);
		carry = d.trim();
		vec_.pushBack(d);
		++irhs;
	}

	while (carry != 0) {							// 处理剩余的进位
		Digit d(carry);
		carry = d.trim();
		vec_.pushBack(d);
	}

} // add(const UInt&)


/* 本整数值乘以十进制位e
 * 要求: e的值必须是 [0, Digit::BASE) 的整数
 *       违反则抛出std::invalid_argument
 */
void UInt::mul(Digit e) {
	Digit::Value carry = 0;							// 进位

	if (e.val >= Digit::BASE)
		throw std::invalid_argument("UInt::mul(Digit e):\n"
									"\trequirement e.val < Digit::BASE violated.\n");

	for (int itor=0; itor < vec_.size(); ++itor) {
		vec_[itor].val *= e.val;
		vec_[itor].val += carry;
		carry = vec_[itor].trim();
	}

	while (carry != 0) {							// 处理剩余的进位
		Digit d(carry);
		carry = d.trim();
		vec_.pushBack(d);
	}

} // mul(Digit)


/* 本整数值乘以整数值rhs
 */
void UInt::mul(const UInt& rhs) {
	UInt result, temp;

	for (int itor=0; itor < rhs.vec_.size(); ++itor) {
		temp = *this;
		temp.mul(rhs.vec_[itor]);
		for (int i=0; i<itor; ++i) {
			temp.vec_.pushFront(Digit(0));				// 乘以10
		}
		result.add(temp);
	}

	*this = result;
} // mul(const UInt&)

/* 在cout打印该无符号整数
 */
void UInt::print() const {
	
	for (int itor = vec_.size()-1; itor >=0; --itor) {
		cout << static_cast<int>(vec_[itor].val);
	}
	
} // print() const