einige schnelle Hilfe beim Vergleich von 2 Dateien mit Binärsuche

Question

so schrieb ich diesen Code für ein Projekt, und ich dachte, es würde funktionieren, aber es war nur einen Vergleich für den ersten Begriff aus einer meiner Dateien (die IkeaWords .txt-Datei). Wo bin ich falsch gelaufen? also das ist was ich geschrieben habe hoffentlich ist es genug.

/*Display each IKEA product name that can be found in the English  dictionary. 
The full list of the 1764 unique IKEA product words is in IKEAwords.txt 
To see if words exist in English, use the 40,444 word English dictionary dictionary.txt, 
where the longest word has 21 characters. To lookup a word in the dictionary consider 
using binary search, 
Print out each word that is found. 
*/ 

#define _CRT_SECURE_NO_WARNINGS 
#define NumberOfWordsInDictionary 40437 
#define MaxWordSize 21+1 
#define NumberOfWordsInIkea 1764 
#include <stdio.h> 
#include <string.h> // for string length 
#include <stdlib.h> // for exit() 

       // Maximum size of any word in the dictionary, + 1 for null 
const char DictionaryFileName[] = "dictionary.txt"; // File name for where dictionary words are found 
const char IkeaFileName[] = "IKEAwords.txt"; 

             //-------------------------------------------------------------------------------------- 
             // Use binary search to look up the word from the .txt file in the dictionary array, 
              //returning index if found, -1 otherwise 
int binarySearch(const char ikeaWord[][MaxWordSize], // word to be looked up 
    const char dictionary[][MaxWordSize],  // the dictionary of words 
    int numberOfDictionaryWords   //number of words in the dictionary 
    )    
{ 
    int low, mid, high;  // array indices for binary search 
    int searchResult = -1; // Stores index of word if search succeeded, else -1 

          // Binary search for word 
    low = 0; 
    high = numberOfDictionaryWords - 1; 
    int i = 0; 
    while (i < MaxWordSize) 
    { 
     while (low <= high) 
     { 
      mid = (low + high)/2; 
      // searchResult negative value means word is to the left, positive value means 
      // word is to the right, value of 0 means word was found 
      searchResult = strcmp(ikeaWord[i], dictionary[mid]); 
      if (searchResult == 0) { 
       // Word IS in dictionary, so return the index where the word was found 
       return mid; 
      } 
      else if (searchResult < 0) 
      { 
       high = mid - 1; // word should be located prior to mid location 
      } 
      else 
      { 
       low = mid + 1; // word should be located after mid location 
      } 
     } 
     i++; 
    } 


    // Word was not found 
    return -1; 
}//end binarySearch() 


//-------------------------------------------------------------------------------------- 
// Read in the words from the dictionary file 
void readWordsInFromDictionaryFile(FILE *pInputFile, char dictionary[][MaxWordSize]) 
{ 
    int index = 0;  // index of dictionary word being read 
    int maxWordLength = 0; 

    // Associate the actual file name with file pointer and try to open it 
    pInputFile = fopen(DictionaryFileName, "r"); 
    // verify that file open worked 
    if (pInputFile == NULL) { 
     printf("Can't open %s. Verify it is in correct location\n", DictionaryFileName); 
     exit(-1); 
    } 

    // Keep reading words while there are any 
    while (fscanf(pInputFile, "%s", dictionary[index]) != EOF) { 
     int tempLength = (int)strlen(dictionary[index]); 
     if (tempLength > maxWordLength) { 
      maxWordLength = tempLength; 
     } 
     index++; 
    } 
    // uncomment out code test array dictionary[][] 
    //printf("There were %d words in the dictionary, with max length %d. \n", index, maxWordLength); 
    fclose(pInputFile); // close the dictionary file 
    printf("There were %d words read from the dictionary with max length %d.\n", index, maxWordLength); 
}//end readInputFile() 

void readWordsInFromIkeaFile(FILE *pInputFile2, char ikeaWord[][MaxWordSize]) 
{ 
    int index2 = 0;  // index of dictionary word being read 
    int maxIkeaWordLength = 0; 

    // Associate the actual file name with file pointer and try to open it 
    pInputFile2 = fopen(IkeaFileName, "r"); 
    // verify that file open worked 
    if (pInputFile2 == NULL) 
    { 
     printf("Can't open %s. Verify it is in correct location\n", IkeaFileName); 
     exit(-1); 
    } 

    // Keep reading words while there are any 
    while (fscanf(pInputFile2, "%s", ikeaWord[index2]) != EOF) 
    { 
     int tempLength2 = (int)strlen(ikeaWord[index2]); 
     if (tempLength2 > maxIkeaWordLength) 
     { 
      maxIkeaWordLength = tempLength2; 
     } 
     index2++; 
    } 
    printf("There were %d words read from the Ikea file with max length %d.\n", index2,maxIkeaWordLength); 
} 
//-------------------------------------------------------------------------------------- 
int main() 
{ 


    char dictionary[NumberOfWordsInDictionary][MaxWordSize]; 
    char ikeaWord[NumberOfWordsInIkea][MaxWordSize]; 


    FILE *pInputFile = fopen(DictionaryFileName, "r");  // file pointer 
    FILE *pInputFile2 = fopen(IkeaFileName, "r"); 
    readWordsInFromDictionaryFile(pInputFile, dictionary); 
    readWordsInFromIkeaFile(pInputFile2, ikeaWord); // used as input 




           // Find index of word in dictionary 
    int index = -1; 
    int j = 0; // counter 
    while(j<NumberOfWordsInIkea) 
    { 
    index = binarySearch(ikeaWord[j], dictionary, NumberOfWordsInDictionary); 

    // Display results 
     if (index != -1) 
     { 
       // word was found, so display it 
      printf("The word \"%s\" was found.\n", dictionary[index]); 
     } 
    j++; 
    } 


    system("pause"); 
    return 0; 
} 

Ich schrieb es in Visual Studio 2015, wenn Sie das auch wissen müssen.

Danke für die Hilfe!

Answer 1

Sie haben mehrere Fehler und unnötige Dinge in Ihrem Code. Ich habe mir die Freiheit genommen, einige Dinge zu ändern, damit es funktioniert (Sie könnten sie bereits gefunden haben, wenn Sie den Hinweisen in den Kommentaren gefolgt sind) und einige Dinge, um es etwas sauberer zu machen (keine Compiler-Warnungen von GCC). Nicht mit MSVS wegen fehlender MSVS überprüft.

#define _CRT_SECURE_NO_WARNINGS 
// changed values to accomodate different data-files sizes 
#define NumberOfWordsInDictionary 99172 
#define MaxWordSize 64 
#define NumberOfWordsInIkea 1393 
#include <stdio.h> 
#include <string.h> 
#include <stdlib.h> 
// from /usr/dict/words (put to lower case) 
const char DictionaryFileName[] = "words.txt"; 
// scraped from http://lar5.com/ikea/ (put to lower case) 
const char IkeaFileName[] = "ikea_names.txt"; 

// ripped 'const' and changed ikeaWord[][] to take a the single entry 
int binarySearch(char *ikeaWord, char dictionary[][MaxWordSize], 
       int numberOfDictionaryWords) 
{ 
    int low, mid, high; 
    int searchResult = -1; 
    low = 0; 
    high = numberOfDictionaryWords - 1; 

    // ripped outer loop because we search for Ikea names one by one 
    while (low <= high) { 
    mid = (low + high)/2; 
    searchResult = strcmp(ikeaWord, dictionary[mid]); 
    if (searchResult == 0) { 
     return mid; 
    } else if (searchResult < 0) { 
     high = mid - 1; 
    } else { 
     low = mid + 1; 
    } 
    } 
    return -1; 
} 

int readWordsInFromDictionaryFile(FILE * pInputFile, 
            char dictionary[][MaxWordSize]) 
{ 
    int index = 0; 
    int maxWordLength = 0; 
    // ripped fopen() because that happened already in main() 

    // Changed from fscanf to fgets because the *scanf() family is a 
    // never ending source of problems, see stackoverflow et al. for endless examples 
    while (fgets(dictionary[index], MaxWordSize - 1, pInputFile)) { 
    int tempLength = (int) strlen(dictionary[index]); 
    // Because of the change from fscanf to fgets we need to snip the newline off 
    // (for "\r\n" endings snipp two) 
    dictionary[index][tempLength - 1] = '\0'; 
    if (tempLength > maxWordLength) { 
     maxWordLength = tempLength; 
    } 
    index++; 
    } 
    // If fgets returns NULL it is either EOF or an error 
    if (ferror(pInputFile)) { 
    fprintf(stderr, "something bad happend while reading dictionary\n"); 
    return 0; 
    } 
    fclose(pInputFile); 
    printf("There were %d words read from the dictionary with max length %d.\n", 
     index, maxWordLength); 
    return 1; 
} 

// snipped off the addition of "2" to the variable names, no need for that 
int readWordsInFromIkeaFile(FILE * pInputFile, char ikeaWord[][MaxWordSize]) 
{ 
    int index = 0; 
    int maxIkeaWordLength = 0; 

    while (fgets(ikeaWord[index], MaxWordSize - 1, pInputFile)) { 

    int tempLength = (int) strlen(ikeaWord[index]); 
    ikeaWord[index][tempLength - 1] = '\0'; 
    if (tempLength > maxIkeaWordLength) { 
     maxIkeaWordLength = tempLength; 
    } 
    index++; 
    } 
    if (ferror(pInputFile)) { 
    fprintf(stderr, "something bad happend while reading ikeawords\n"); 
    return 0; 
    } 
    printf("There were %d words read from the Ikea file with max length %d.\n", 
     index, maxIkeaWordLength); 
    return 1; 
} 

//-------------------------------------------------------------------------------------- 
int main() 
{ 
    char dictionary[NumberOfWordsInDictionary][MaxWordSize]; 
    char ikeaWord[NumberOfWordsInIkea][MaxWordSize]; 

    int res; 
    // added error-checks 
    FILE *pInputFile = fopen(DictionaryFileName, "r"); 
    if (pInputFile == NULL) { 
    fprintf(stderr, "Can't open %s. Verify it is in correct location\n", 
      DictionaryFileName); 
    exit(EXIT_FAILURE); 
    } 
    FILE *pInputFile2 = fopen(IkeaFileName, "r"); 
    if (pInputFile2 == NULL) { 
    fprintf(stderr, "Can't open %s. Verify it is in correct location\n", 
      IkeaFileName); 
    exit(EXIT_FAILURE); 
    } 
    if ((res = readWordsInFromDictionaryFile(pInputFile, dictionary)) == 0) { 
    fprintf(stderr, "Error in reading dictionary\n"); 
    exit(EXIT_FAILURE); 
    } 
    if ((res = readWordsInFromIkeaFile(pInputFile2, ikeaWord)) == 0) { 
    fprintf(stderr, "Error in reading ikea-file\n"); 
    exit(EXIT_FAILURE); 
    } 

    int index = -1; 
    int j = 0; 
    while (j < NumberOfWordsInIkea) { 
    index = binarySearch(ikeaWord[j], dictionary, NumberOfWordsInDictionary); 

    if (index != -1) { 
     printf("The word \"%s\" was found.\n", dictionary[index]); 
    } 
    j++; 
    } 
// Seems to be useful when run in MS-Windows 
#if defined _WIN32 || defined WIN32 || defined WIN64 || defined _WIN64 
    sytem("pause"); 
#endif 
    exit(EXIT_SUCCESS); 
} 

Ich habe nicht jede Ecke poliert, es braucht noch etwas Arbeit. Zum Beispiel: Die zwei Funktionen, die die beiden Dateien lesen, machen dasselbe, nur für eine andere Datei und ein anderes Wörterbuch. Das kann mit einer einzigen Funktion gemacht werden. Der Name der Dateien, die Länge der Datei und die Länge der Einträge dieser Dateien sind fest, sie können dynamisch gemacht werden, um verschiedene Eingaben ohne Neukompilierung verwenden zu können.

Aber überall: nicht schlecht für den Start!