Thread: Just a tiny little problem...

Daniel check this one:

Code:

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

#define SIZE 4
int main()
{
char strings[SIZE][SIZE]={"Xbc", "Zbc", "Hbc", "Dbc"};

printf("Before Sort:\n\n");
print_str_array(strings,SIZE);

str_bsort(strings, SIZE);

printf("\nAfter Sort:\n\n");
print_str_array(strings,SIZE);

}


int str_bsort(char strings[0][SIZE], int asize)
{
int i, j;
char temp[SIZE];

for(i=0; i<asize; i++)

for(j=0; j<asize-1; j++)
if(strcmp(strings[ j ], strings[ j+1 ])>0)
{
strcpy(temp, strings[ j ]);
strcpy(strings[ j ], strings[ j+1 ]);
strcpy(strings[ j+1 ], temp);
}


}


int print_str_array(char strings[0][SIZE], int asize)
{
int i;

for(i=0; i<asize; i++)
printf("%s\n",strings[i]);

}

Just a quick fix on your code zahid

Code:

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

#define SIZE 4

void str_bsort(char strings[][SIZE], int asize);
void print_str_array(char strings[][SIZE], int asize);

int main(void)
{
  char strings[SIZE][SIZE]={"Xbc", "Zbc", "Hbc", "Dbc"};

  printf("Before Sort:\n\n");
  print_str_array(strings,SIZE);

  str_bsort(strings, SIZE);

  printf("\nAfter Sort:\n\n");
  print_str_array(strings,SIZE);

  return EXIT_SUCCESS;
}

void str_bsort(char strings[][SIZE], int asize)
{
  int i, j;
  char temp[SIZE];

  for(i=0; i<asize; i++)
    for(j=0; j<asize-1; j++)
      if(strcmp(strings[ j ], strings[ j+1 ])>0){
        strcpy(temp, strings[ j ]);
        strcpy(strings[ j ], strings[ j+1 ]);
        strcpy(strings[ j+1 ], temp);
      }
}

void print_str_array(char strings[][SIZE], int asize)
{
  int i;
  for(i=0; i<asize; i++)
    printf("%s\n",strings[i]);
}

It may be different on your compiler, but on mine functions won't accept an array size of 0. And you forgot to prototype your functions.

-Prelude

why does a double subscripted array will solve the problem?

more importantly, what is the problem with the array of strings?

thnx

Originally posted by Nutshell
ok, so when i save strings in an array of pointers, i can't modify it right?

Thnx

Yup.....just as Prelude said earlier

also, my books also says that using a double-subscripted array to store strings is not as efficient as an array of pointers, if most of the strings are shorter than the longest string.

This is a memory vs proccesor usage issue. It can take less memory, but it takes more work to access the strings. It really all depends.

Now consider the two following initialiations....

Code:

char * pChar = "Hello World!";
char aChar[] = "Hello World!";

Both create an array in memory, but there are two important differences....

1) You can change the value of pChar, you can't change the value of aChar.
2) You can change the memory pointed at by aChar. Changing the memory pointed at by pChar is undefined.

Since your array is an array of char *s, the effect of changing the memory pointed at by them is undefined (incidentally, it ran fine on my computer... *shrug*).

Even if it did work, consider what would happen if you actually had strings that were different length. Say you try to swap the contents of a 5 character string and a 3 character string... one of the strings wouldn't have enough room. Therefore, you really need to just use an array of strings, all of which have the same length... which is basically a 2d array, so that you can move the largest string into any part of the array.




Still, there's a better way to do it....

Code:

if ( strcmp( a[ j ], a[ j + 1 ] ) > 0 ) {
            strcpy( hold, a[ j ] );
            strcpy( a[ j ], a[ j + 1 ] );
            strcpy( a[ j + 1 ], hold );
         }

Okay, so a[j] points at one string, and a[j+1] points at another, and you want to swap them. Above you do so by moving the contents of the string.

Code:

if ( strcmp( a[ j ], a[ j + 1 ] ) > 0 ) {
            hold = a[ j ];
            a[ j ] = a[ j + 1 ] );
            a[ j + 1 ] = hold );
         }

In this segment of code, the swap is done by just swapping the addresses of the strings. I believe this way should work.

It's kinda like if two people want to swap furniture, they can either move the furniture between their houses, or they can just swap houses.

Also, instead of keeping a size variable, you're probably better off using something like this...

Code:

bubbleSort_strings( strings, sizeof(strings) / sizeof(strings[0]));

As long as strings is an array, this will give you the number of elements in the array.

Study the bubble sort syntax! I hate your guys ugly syntax!

Code:

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

void bubbleSort_strings( char *a[], const int size );

int main()
{
   const int size = 4;
   int i;
   char *strings[ size ] = { "DEF", "CDE", "BBB", "ABC" };

   bubbleSort_strings( strings, size );

   printf( "Sorted list of strings are: \n" );

   for ( i = 0; i < size; i++ )
      printf( "%s ", strings[i] );

   return 0;
}


void bubbleSort_strings( char *a[], const int size )
{
   int i,ii;
   char * temp;

   for ( i = 0; i < size ; i++ )
   {
      for ( ii = i + 1; ii < size ; ii++ )
	  {
         if ( strcmp( a[ i], a[ ii ] ) == 1 ) 
		 {
            temp = a[ i ];
            a[ i ] = a[ ii ];
            a[ ii ] = temp;
         }
	  }
	}
}

You only have to switch the array indexes.

hey thnx trollking and questionC for the explanation, now i get it.

many thnx

so what if you are going to create a two dimensional array based on an input of an fscanf? such as this

PHP Code:

fscanf(fPtr,"%d",&nDimension);
char chArray[nDimension][nDimension]; 


and then fill it using nested for loops. how would you go about accomplishing this?

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