私はC++でプログラムに取り組んでおり、絞首刑執行人のコンピューターと対戦することになっており、特定の.cppファイルをベクトルの使用からリンクリストの使用に変換することになっています。私はほぼ完了しているように見えますが、コンピュータが文字を誤って推測するたびにプログラムがクラッシュするこの奇妙なバグが発生し続けています。プログラムをデバッガーで実行すると、「プログラムはSIGSEGVを受信しました、セグメンテーション違反」というメッセージがコールスタックにこの情報とともにポップアップ表示されます。
libstdc++6!_ZNSsC1ERKSs()
Guesser::guessACharacter(this=0x28feac) Line 56
main(argc=1, argv=0x7725a8) Line 30
クラッシュは、Guesser ::guessACharacter関数の9行目の問題につながるようです。この関数では、現在のノードからの情報を一時変数に入れようとします。次のようになります。
string word = current->data;
完全なコードは次のとおりです。
#include "guesser.h"
#include "game.h"
#include <iostream>
#include <fstream>
using namespace std;
const std::string Guesser::alphabet = "abcdefghijklmnopqrstuvwxyz";
// Initialize the guesser for a game wit hthe indicated wordlength,
// using words from an indicated file.
Guesser::Guesser (int wordLength, const char* wordListFilename)
{
for (int i = 0; i < 26; ++i)
charactersTried[i] = false;
string word;
ifstream in (wordListFilename);
while (in >> word)
{
if (word.size() == wordLength)
{
// word is of desired length
if (word.find_first_not_of(alphabet) == string::npos) {
// word contains only lowercse alphabetics
//cerr<<"data before possible soln.:/n"<<possibleSolutions->data<<endl;
possibleSolutions->data = word;
//cerr<<"data after possible soln.:/n"<<possibleSolutions->data<<endl;
possibleSolutions = possibleSolutions -> next;
}
}
}
in.close();
}
/**
* Scan the words that are possible solutions so far, counting, for
* each letter not already tried, the number of words with that letter.
* Guess the letter that occurs in the most words.
*/
char Guesser::guessACharacter()
{
int counts[26];
for (int i = 0; i < 26; ++i)
counts[i] = 0;
// Count the number of words in which each letter can be found
for(ListNode* current = possibleSolutions; current != NULL; current = current-> next)
{
//cerr<<"data before possible soln.:/n"<<possibleSolutions->data<<endl;
string word = current->data;
//cerr<<"data in word:/n"<<word<<endl;
for (char c = 'a'; c <= 'z'; ++c)
{
if (!charactersTried[c- 'a'])
{
// Character c has not been tried yet
if (word.find(c) != string::npos)
// c is in this word
++counts[c - 'a'];
}
}
}
// Find the character that occurs in the most words
char guess = ' ';
int maxSoFar = -1;
for (char c = 'a'; c <= 'z'; ++c)
{
if (counts[c - 'a'] > maxSoFar)
{
guess = c;
maxSoFar = counts[c - 'a'];
}
}
if (maxSoFar <= 0)
{
guess = 'a';
while (charactersTried[guess-'a'])
++guess;
}
charactersTried[guess-'a'] = true;
return guess;
}
/**
* Following a successful guess of a letter in the word, make a pass through
* the possibleSolutions, removing all words that do not contain the
* guess character in the positions indicated in wordSoFar.
*/
void Guesser::characterIsInWord (char guess, const string& wordSoFar)
{
ListNode* remainingSolutions = 0;
for(ListNode* current = possibleSolutions; current != NULL; current = current-> next)
{
string wd = current-> data;
bool OK = true;
for (int k = 0; OK && k < wordSoFar.size(); ++k)
{
if (wordSoFar[k] == guess)
{
if (wd[k] != guess)
{
OK = false;
}
}
}
if (OK)
{
//cerr << "Keeping " << wd << endl;
remainingSolutions->data = wd;
//possibleSolutions->next = remainingSolutions;
}
}
possibleSolutions = remainingSolutions;
}
/**
* Following a mistaken guess of a letter in the word, make a pass through
* the possibleSolutions, removing all words that contain the
* guess character.
*/
void Guesser::characterIsNotInWord (char guess)
{
ListNode* remainingSolutions;
for(ListNode* current = possibleSolutions; current != NULL; current = current-> next)
{
string wd = current->data;
if (wd.find(guess) == string::npos)
{
remainingSolutions = new ListNode(wd, remainingSolutions);
}
}
possibleSolutions = remainingSolutions;
}
/**
* Guesser has lost the game. Look at the provider's actual word
* and gripe a bit about losing.
*/
void Guesser::admitToLoss (std::string actualWord, const string& wordSoFar)
{
bool match = actualWord.size() == wordSoFar.size();
for (int i = 0; match && i < actualWord.size(); ++i)
{
match = wordSoFar[i] == Game::FILL_CHARACTER ||
wordSoFar[i] == actualWord[i];
}
if (!match)
{
cout << "Ummm...your word '" << actualWord
<< "' does not match the patterh '"
<< wordSoFar <<"'.\nDid you make a mistake somewhere?"
<< endl;
}
else
{
for (int i = 0; match && i < actualWord.size(); ++i)
{
if (wordSoFar[i] == Game::FILL_CHARACTER
&& charactersTried[actualWord[i]-'a'])
{
cout << "Did you forget to mention the '"
<< actualWord[i]
<< "' in position " << i+1 << "?"
<< endl;
return;
}
}
for (ListNode* current = possibleSolutions;(!match) && current !=
NULL; current = current-> next)
{
match = (actualWord == current->data);
current = current->next;
match = match && (current != 0);
}
//match = match && (current != 0);
if (match)
{
cout << "OK, I might have guessed that eventually." << endl;
}
else
{
cout << "Interesting, I don't know that word. Are you sure you\n"
<< "spelled it correctly?." << endl;
}
}
}
その答えは、私の顔をじっと見つめているような気がしますが、理解できません。ここで私が間違っていることを他の誰かが簡単に見つけられるかどうか疑問に思いました。