Trying to compare strings in 2d array

Question

So I have created a file that has a bunch of words in it, and my program is supposed to open the file, put all of the words in an array, and then compare the strings to see if any are exact matches. It opens the file and populates the array, but the problem comes when I am trying to compare the strings.. Can anyone tell me how to go about fixing why this isn't comparing properly?

My words file:

Google Twitter Facebook Twitter gmail Flyer city 
phone Google cookie Facebook Flyer grill fork silver tornado dirty 
blue grill lemon

Code:

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

int main(void) 
{ 
    FILE *words; 
    char words_array[20][17];
    int x=0; 
    int y=0;
    int pairs = 0;
    words=fopen("words.dat","r"); 
    if(words==NULL) 
        printf("\n\nwords.dat was not properly opened.\n");
      else
        {
                 for(x = 0 ; x < 20 ; x++ ) 
                 { 
            fscanf(words,"%s",&words_array[x][y]); 
                 } 
                 fclose(words); 
                         for(x = 0 ; x < 20 ; x++ )
                       printf("Word #%d is %s \n", x + 1, words_array[x]); 

            /*start of comparison*/

                for(x=0;x<20;x++)
                        {
              for(y=0;y<20;y++)
                           {
            if (strcmp (words_array[x], words_array[x+1])==0)
                pairs++;
                       }
                /*end of comparisons*/
                         }
                printf("%d \n",pairs);


        }
    return(0); 
}

Output:

Word #1 is Google 
Word #2 is Twitter 
Word #3 is Facebook 
Word #4 is Twitter 
Word #5 is gmail 
Word #6 is Flyer 
Word #7 is city 
Word #8 is phone 
Word #9 is Google 
Word #10 is cookie 
Word #11 is Facebook 
Word #12 is Flyer 
Word #13 is grill 
Word #14 is fork 
Word #15 is silver 
Word #16 is tornado 
Word #17 is dirty 
Word #18 is blue 
Word #19 is grill 
Word #20 is lemon 
0

jpw · Accepted Answer · 2013-11-11T20:57:55.980

You are only comparing the current row with the next. Change the loop with strcmp to:

for(x=0; x<20; x++) {
    for(y=x+1; y<20; y++) {
        if (strcmp (words_array[x], words_array[y])==0)
            pairs++;
    }   
}

This will find five pairs in your sample data:

 Google
 Twitter
 Facebook
 Flyer
 grill

On a side note you might want to add a defined constant for the number of rows at the beginning of the program (between the #includes and main) so you don't have to replace the 20everywhere if you want to change the number of lines read (and of course the same can be said for the word length):

#define MAXLINES 20
#define MAXLENGTH 17

and then you can use those constants everywhere you now have 20 and 17.

Trying to compare strings in 2d array

1 Answers1