匹配相同字母的单词

Question

I am trying to match two words and then print them out eg 'act' and 'cat' have 'a,'c' and 't' in them so they match. here is my code:

#include <stdio.h>
#include <stdlib.h>

main()
{
  FILE        *fptr;
  char        words[100], input[100], store[1000][100] 
  char        ch
  int         i,j,k,z,b,*ptr;

  ptr = &b;

  fptr = fopen("d:\\words.txt","r");
  if (fptr == NULL)
  {
           printf("Could not open file");
           exit(1);
  }

  printf("Enter the scrambled word: ");
  fflush(stdin);
  fgets (input,sizeof(input),stdin);

  i = 0;
  while (fgets(words,sizeof(words),fptr) != NULL)
  {     
        if (strlen(input) == strlen(words))
        {
           strcpy(store[i],words);
           ++i;
        }
  }
  //this is where the problem is:
  /*am trying to match the letters in two words, if they don't match then store 1 in b,
  if b=0 then print out the word which matched with string 'input'*/
  for(z = 0; z < 1000; ++z)
  {
        b = 0;
        for(j = 0; j < strlen(input); ++j)
        {
              for(k = 0; k < strlen(store[z]); ++k)
              {
                    if(input[j] != store[z][k])
                        *ptr = 1;          
              }
        }
        if(*ptr == 0)
        {          
                   printf("Word #%2d is: %s\n", z, store[z]);   
        }
  }



  fflush(stdin);
  getchar();
}

Please I really need help. Am sorry if I haven't made my question clear.

Answer 1

Sorting the letters in both strings and then comparing them is one of the simpler ways of doing what you require. (assuming you are familiar with sorting)

It may not be the most efficient but I then again, worrying too much about efficiency is usually best left until after you have a working solution and performance metrics.

If you want some more efficient methods to detect if two words are anagrams, check out the link provided by Mats Petersson, Optimizing very often used anagram function

Answer 2

Something like this could also work.. (sorry ugly reading code, very busy with something else)...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <Windows.h>

#include <string>
#include <list>
#include <map>
#include <sstream>
#include <algorithm>

using namespace std;

map< string, list<string> > items;
int c = 0;

void readFile() {
        FILE * f = fopen( "c:\\t\\words.txt", "r" );
        fseek(f, 0L, SEEK_END);
        int size = ftell(f);
        fseek(f, 0L, SEEK_SET);
        char * data = (char*)malloc(size);
        fread(data, size, 1, f);

        string s = string(data);
        istringstream reader(s);
        while(reader) {
            string sub;
            reader >> sub;

            string original = sub;
            sort( sub.begin(), sub.end() );

            items[sub].push_back(original);        
            c++;
        }


        free(data);
        fclose(f);
}

bool     check( const string & v ) {
    string requestStr = v;
    sort( requestStr.begin(), requestStr.end() );
    printf("Requested: %s [%s]\n", v.c_str(), requestStr.c_str());

    if (items.find(requestStr) == items.end()) {
        printf("Not found\n");
        return false;
    }

    list<string>::iterator it = items[requestStr].begin();

    while (it != items[requestStr].end()) {
        printf("Found: %s\n", (*it).c_str());       
        it++;
    }
}

int main(int argc, char ** argv) {
    long t1 = GetTickCount();
    readFile();
    printf("Read wordlist (%i): %li ms\n", c, GetTickCount() - t1 );

    string str = "holiday";
     t1 = GetTickCount();
    check(str);
    printf("Time: %li ms\n",  GetTickCount() - t1 );


    str = "tac";
     t1 = GetTickCount();
    check(str);
    printf("Time: %li ms\n",  GetTickCount() - t1 );

    str = "dfgegs";
     t1 = GetTickCount();
    check(str);
    printf("Time: %li ms\n",  GetTickCount() - t1 );

}

results on 109000 words file

Read wordlist (109583): 5969 ms
Requested: holiday [adhiloy]
Found: holiday
Time: 0 ms
Requested: tac [act]
Found: act
Found: cat
Time: 0 ms
Requested: dfgegs [defggs]
Not found
Time: 0 ms

120000 searches takes 7188ms, so around 0.0599ms per search...