Thread: qsort() in Array of Pointer to String

I m trying to sort an Array of Pointer to String using qsort() . Result doesnt show the sorted string , Have a look at the code

Code:

// qsort() in Array of Pointer to String 

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

int cmp(const void *, const void *);

main(void)
{
    char *s[] = {
                   "Gaurav",
                   "Vaibhav",                   
                   "Garima",
                   "Amit"                     
                };
                
    qsort( (char*)s, 4 , sizeof(s[0]), cmp);
    
    int i = 0;
    while(i<4)
    {
        printf("\t%s\n",s[i]);
        i++;      
    }
             
    getch();       
}

int cmp(const void *x, const void *y)
{
    return(strcmp((char*)x,(char*)y));       
}

actually i have already tried my hand at bsearch() over Array of Pointer to String assuming Strings are sorted in assending order, and its working, here is the code

Code:

// bsearch() in Array of Pointer to String <assuming Sorted>

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

int cmp(const void *, const void *);

main(void)
{
    char *s[] = {
                   "Amit",
                   "Garima",
                   "Gaurav",
                   "Vaibhav"                     
                };
                
    char *str = "Vaibhav";
    
    char **found = (char**)bsearch( (char*)&str, (char*)s, 4 , sizeof(s[0]) , cmp);
    
    if(found!=NULL)
            printf("Found!");
    else
            printf("Not Found!");
             
    getch();       
}

int cmp(const void *x, const void *y)
{
    return(strcmp((char*)x,(char*)y));       
}

here, too i used only pointer to char in my cmp() and not pointer to pointer to char and it was working, so y not on qsort() ?

ok!

so, my cmp() function is passed pointer to pointer to Strings stored.

strcmp() function declaration says:-

Code:

int strcmp(const char *s1, const char *s2);

this means strcmp() expects pointer to strings , so i need to dereference my pointers passed to cmp() only once. so i tried this

Code:

int cmp(const void *x, const void *y)
{
    return(strcmp((char*)(*x),(char*)(*y)));       
}

but i m getting an error !

thanx a ton! , it is working, here is what i hv done !

Code:

int cmp(const void *x, const void *y)
{
    return(strcmp(*((char**)x),*((char**)y)));       
}

yeah right