'recursion'에 해당되는 글 1건

먼저 기본적으로 세팅하는 부분이다. 특별한 것은 없다.

#include <iostream>

using namespace std; 

#define MAX_LENGTH_OF_PHONE_NUMBER 7
// 0, 1 are not translated into alphabets.
string numStr[8] = {"ABC", "DEF", "GHI", "JKL", "MNO", "PRS", "TUV", "WXY"};

void printTelephoneWords(char*, char*, int);
void printTelephoneWordsNonRec(char*, char*);

int main() {
	char phone[MAX_LENGTH_OF_PHONE_NUMBER+1];	// original phone number
	char tphone[MAX_LENGTH_OF_PHONE_NUMBER+1]; // translated words

	while (true) {
		memset(tphone, 0x00, MAX_LENGTH_OF_PHONE_NUMBER+1);
		cin >> phone;
		if (cin.eof())
			break;
		cout << "With Recursion" << endl;
		printTelephoneWords(phone, tphone, 0);			
		
		cout << "With Iteration" << endl;
		printTelephoneWordsNonRec(phone, tphone);
	}
	
	return 0;
}

void printTelephoneWords(char *phone, char *tphone, int index) {
	if (index == strlen(phone)) {
		cout << tphone << endl;
		return;
	}

	for (int j = 0; j < 3; j++) {
		if (phone[index] == '0' || phone[index] == '1')
			tphone[index] = phone[index];
		else
			tphone[index] = numStr[phone[index]-'2'].at(j);	
		
		printTelephoneWords(phone, tphone, index+1);

		if (phone[index] == '0' || phone[index] == '1')
			return;
	}	
}

void printTelephoneWordsNonRec(char *phone, char *tphone) {
	int len = strlen(phone);
	
	for (int i = 0; i < len; i++) {
		if (phone[i] == '0' || phone[i] == '1') 
			tphone[i] = phone[i];
		else
			tphone[i] = numStr[phone[i]-'2'].at(0);
	}
		
	while (true) {
		cout << tphone << endl;

		for (int i = len - 1; i >= 0; i--) {
			if (tphone[i] == '0' || tphone[i] == '1') {
				tphone[i] = phone[i];
			} else if (tphone[i] == numStr[phone[i]-'2'].at(2)) {
				tphone[i] = numStr[phone[i]-'2'].at(0);
			} else if (tphone[i] == numStr[phone[i]-'2'].at(0)) {
				tphone[i] = numStr[phone[i]-'2'].at(1);
				break;
			} else if (tphone[i] == numStr[phone[i]-'2'].at(1)) {
				tphone[i] = numStr[phone[i]-'2'].at(2);
				break;
			}
			
			if (i == 0) return;
		}
	}	
}