please help on string sorting

[barbiegirl]

hi everyone,
i was writing an application, with the c language, which asks the user to give the number of strings to sort, and then sort'em, but i had some problems that i can't figure out, would u please help me

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

void getting(char *words[], int num);
void sort(char *words[], int n);

int i=0;

int main(int argc, char *argv[])
{

	char (*word)[30]=NULL;
	int n=0;

	getting(word, n);
	sort(word, n);

	system("pause");
	return EXIT_SUCCESS;
}

void getting(char *words[], int num)
{
	printf("how many words u wanna sort\t");
	scanf("%ld", &num);
	getchar();

	words=(char *)calloc(num, sizeof(char));

	for(i=0; i<num; i++)
	{
		printf("enter the %ldth word : ", i);
		fgets(&words[i], 30, stdin);
	}

}

void sort(char *words[], int n)
{
	int k=1, sorted=1;
	char tmp[30];

	do
	{
		sorted=1;
		for(i=0; i<n-k; i++)
		{
			if(strcmp(words[i], words[i+1])>0)
			{
				strcpy(tmp, words[i]);
				strcpy(words[i], words[i+1]);
				strcpy(words[i+1], tmp);
				sorted=0;
			}
		}
		k++;
	}
	while(sorted!=1);

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

[Adak]

Looks like the variable "num" is not returned to main, the variable "n" is never passed the value of num.

That leaves your sorting function with 0 strings that are being asked to sort. Return num and assign it to n, and see if that doesn't help.

[barbiegirl]

Looks like the variable "num" is not returned to main, the variable "n" is never passed the value of num.

That leaves your sorting function with 0 strings that are being asked to sort. Return num and assign it to n, and see if that doesn't help.

i passed num as a pointer but didnt work, my main problem i guess is when getting the strings, i found a solution using "char words[MAXWORDS][MAXLENGTH]" but i wanna do it "char *words[]",
thnx for ur help

[Adak]

If you want to use a pointer, then use a pointer, not the indices.

Read up on the -> operator, and you'll be off and running.

[Jishnu]

printf("how many words u wanna sort\t");
	scanf("%ld", &num);
	getchar();

	words=(char *)calloc(num, sizeof(char));

Put the above statements in the main() function and the code should be fine.

EDIT: You'll also adjust the scope of some variables. Do that, too. Post any further problems you have.

[barbiegirl]

printf("how many words u wanna sort\t");
	scanf("%ld", &num);
	getchar();

	words=(char *)calloc(num, sizeof(char));

Put the above statements in the main() function and the code should be fine.

EDIT: You'll also adjust the scope of some variables. Do that, too. Post any further problems you have.

i tried it, but im having a break when it goes to "strcmp(words, words[i+1])", it tells me access reading violation or stuff like that

PS: i use visual C

[Sorrofix]

You've got some memory allocation issues in your code. On top of that, you're passing a pointer of a pointer to fgets(), while fgets() expects a pointer to a null-terminated string.

[ssharish2005]

As it’s been previously mentioned that, there are quite a few problems in your code. Which you might have to sit down and think about. I will point you out few error which you have made.

1.The memory allocation for char point word is not right.

Char (*word)[30];
	
	Has to be like this

	Word = malloc( sizeof (char *[30] ) * 10 );
	// Please note you need to do some error checking down, to avoid further problem

2.Reading string through fgets is really a good practice, but at the same time you need to understand the on how to use those function and their parameter list. The fgets function for a void * pointer, but not .void ** pointer. Which means that, the usage of the fgets function should be as follow

fgets( word[i], 30, stdin);

To makes more for easy and, I have written few sample codes which might give you some idea on how to read string in two ways .One is through a Array of char pointer methods and the other one through pointer to pointer methods. Have a look at it. You should get some idea on how to use them.

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

void readstring( char (*word)[30] )
{
     int i;
     for( i = 0; i < 10; i++ )
         fgets( word[i], 30, stdin );
}

int main()
{
    char (*word)[30];
    int i, num;
    
    printf("Enter the number of word you want to sort\n?");
    scanf("%d", &num );
    
    word = malloc( sizeof(char *[30]) * 10 );
    /* dont forget to do some error checking here */
      
    readstring( word );    
    
    for(i=0;i<num;i++)
       printf("%s\n", word[i] );

    free( word );
    getchar();
    return 0;
} 

/* ------------------------------------------------------------------ */

int main()
{
    char **word;
    int num, i;
    
    printf("Enter the number of word you want to sort\n?");
    scanf("%d", &num );
    
    word = malloc( sizeof( char * ) * num );
    /* dont forget to do some error checking here */
    
    for( i = 0; i < num; i++ )
         word[i] = malloc( sizeof( char *) * 30 );
         /* dont forget to do some error checking here */
         
    for( i = 0; i < num; i++ )
         fgets( word[i], 30, stdin );
        
    for(i=0;i<num;i++)
       printf("%s\n", word[i] );
 
    for(i=0;i<num;i++)
       free( word[i] );
    
    free( word );
    
    getchar();
    return 0;
}

ssharish

[barbiegirl]

As it’s been previously mentioned that, there are quite a few problems in your code. Which you might have to sit down and think about. I will point you out few error which you have made.

1.The memory allocation for char point word is not right.

Char (*word)[30];
	
	Has to be like this

	Word = malloc( sizeof (char *[30] ) * 10 );
	// Please note you need to do some error checking down, to avoid further problem

2.Reading string through fgets is really a good practice, but at the same time you need to understand the on how to use those function and their parameter list. The fgets function for a void * pointer, but not .void ** pointer. Which means that, the usage of the fgets function should be as follow

fgets( word[i], 30, stdin);

To makes more for easy and, I have written few sample codes which might give you some idea on how to read string in two ways .One is through a Array of char pointer methods and the other one through pointer to pointer methods. Have a look at it. You should get some idea on how to use them.

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

void readstring( char (*word)[30] )
{
     int i;
     for( i = 0; i < 10; i++ )
         fgets( word[i], 30, stdin );
}

int main()
{
    char (*word)[30];
    int i, num;
    
    printf("Enter the number of word you want to sort\n?");
    scanf("%d", &num );
    
    word = malloc( sizeof(char *[30]) * 10 );
    /* dont forget to do some error checking here */
      
    readstring( word );    
    
    for(i=0;i<num;i++)
       printf("%s\n", word[i] );

    free( word );
    getchar();
    return 0;
} 

/* ------------------------------------------------------------------ */

int main()
{
    char **word;
    int num, i;
    
    printf("Enter the number of word you want to sort\n?");
    scanf("%d", &num );
    
    word = malloc( sizeof( char * ) * num );
    /* dont forget to do some error checking here */
    
    for( i = 0; i < num; i++ )
         word[i] = malloc( sizeof( char *) * 30 );
         /* dont forget to do some error checking here */
         
    for( i = 0; i < num; i++ )
         fgets( word[i], 30, stdin );
        
    for(i=0;i<num;i++)
       printf("%s\n", word[i] );
 
    for(i=0;i<num;i++)
       free( word[i] );
    
    free( word );
    
    getchar();
    return 0;
}

ssharish

thank you very very much, that was very helpful, now my lil program works much better, thnx again