Thread: Search of string array isn't working correctly

Hi all -

I've written this code to search an array of strings for a given string. Here it is -

Code:

 


/*  search.c  */ 

/*  Function to search an array of strings */
/*  to find a given string. */ 

/*  This code is released to the public domain. */ 
/*  "Share and enjoy...."  :)    */ 


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


/* Array of strings. */ 
static const char *kw_strings[] = { 
   "select", "from", "where", "and", "or", "not", "in", "is", "null" 
    } ; 
   
    
/*  Search function.  */ 
void search(const char *arr[], char *str) { 
    int len = sizeof(arr) / sizeof(arr[0]) ; 
    int i;
    
    for (i=0; i<len; i++) { 
        if ( !strcmp(arr[i] , str ) )  {   
            printf("%s \n", "Found"); 
     } 
        else  { 
            printf("%s \n", "Not Found");        
    } 
    
 }  /* For */     

}  /* search */ 


int main() { 

  search(kw_strings , "select") ;   
  
  search(kw_strings , "from") ;   
  
  search(kw_strings , "foobar") ; 
  
  search(kw_strings , "I like moose") ; 
       
  return 0; 
    
}

This *should* result in the first two searches succeeding.
However, I'm getting the first one succeeding and then three fails. Any help on why this is is very much appreciated!

- Andy ( latte123 )

You need to pass the size of the array along with the array, rather than calculating it in the search() function, as arr in the search() function is just a pointer. search() cannot determine the size of the "array" being passed.

Originally Posted by rstanley

You need to pass the size of the array along with the array, rather than calculating it in the search() function, as arr in the search() function is just a pointer. search() cannot determine the size of the "array" being passed.

Ahhh...... thanks for that, rstanley! Should be an easy fix.....
Thanks again, bye for now -
- Andy

Hi again all -

I've got the code working perfectly now. The search now returns an int - code follows -

Code:

 

/*  search.c  */ 

/*  Function to search an array of strings */
/*  to find a given string. */ 

/*  This code is released to the public domain. */ 
/*  "Share and enjoy...."  :)    */ 


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



/* Array of strings. */ 
char *kw_strings[] = { 
   "select", "from", "where", "and", "or", "not", "in", "is", "null" 
    } ; 
   
    
/*  Search function.  */ 
int search(char *arr[], char *str) { 
    
    int i;  
    int found_match;
    
    for (i=0; i<9; i++) { 
        if ( !strcmp(arr[i] , str ) )  {   
            found_match = 1;        
            break; 
    }   else found_match = 0;    
 }  /* For */     

    return found_match; 
}  /* search */ 



int main() { 


  int i = search(kw_strings , "select") ;   
  
  int j = search(kw_strings , "from") ;   
  
  int k = search(kw_strings , "null") ;   
  
  int l = search(kw_strings , "foobar") ; 
  
  int m = search(kw_strings , "I like moose") ; 
 
  printf("%d %d %d %d %d \n", i,j,k,l,m); 
        
  return 0; 
    
}

The first three searches succeed and return 1, as expected. Woohoo!

- Andy ( latte123 )

No, you should make the search() function generic by PASSING the array dimension!!!

Instead of:

Code:

int search(char *arr[], char *str)
{
...
}

You should make it:

Code:

int search(char *arr[], int dim, char *str)
{
...
}

I'll let you fill in the code. This way you may pass different arrays to the function, with different sizes.

Hi rstanley -

Done - thanks for that! Here's the code for anyone interested -

Code:

/*  search.c  */ 

/*  Function to search an array of strings */
/*  to find a given string. */ 

/*  This code is released to the public domain. */ 
/*  "Share and enjoy...."  :)    */ 


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



/* Array of strings. */ 
char *kw_strings[] = { 
   "select", "from", "where", "and", "or", "not", "in", "is", "null" 
    } ; 
   
    
/*  Search function.  */ 
int search(char *arr[], int dim, char *str) { 
    
    int i;          
    int found_match;
    
    for (i=0; i<dim; i++) { 
        if ( !strcmp(arr[i] , str ) )  {   
            found_match = 1;        
            break; 
    }   else found_match = 0;    
 }  /* For */     

    return found_match; 
}  /* search */ 



int main() { 
 
  int i = search(kw_strings, 9, "select") ;   
  
  int j = search(kw_strings, 9, "from") ;   
  
  int k = search(kw_strings, 9, "null") ;   
  
  int l = search(kw_strings, 9, "foobar") ; 
  
  int m = search(kw_strings, 9, "I like moose") ; 
 
  printf("%d %d %d %d %d \n", i,j,k,l,m); 
        
  return 0; 
    
}

Thanks for your help!
- Andy