Question

I am using qsort function in c..its a in built function…it works well for strings having length less than 7..on strings whose length > 7, it gives “Segmentation fault (core dumped)”

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAX 100

static int cmpr( const void *a, const void *b) { 
    return strcmp( *(char **)a, *(char **)b);
}


int main()
{
    int t;
    char str1[MAX],str2[MAX];

    scanf("%d",&t);

    while(t--)
    {
    scanf("%s %s",str1,str2);

    int len1=strlen(str1)/sizeof(char *);
    int len2=strlen(str2)/sizeof(char *);

    qsort(str1, len1, sizeof(char *), cmpr);
    qsort(str2, len2, sizeof(char *), cmpr);

    if((strstr(str1,str2)!=NULL)&& (strlen(str1)==strlen(str2)))
        printf("YES");
    else if((strstr(str2,str1)!=NULL) && (strlen(str1)==strlen(str2)))
        printf("YES");
    else if((strstr(str2,str1)!=NULL) && (strlen(str1)!=strlen(str2)))
        printf("NO");
    else if((strstr(str1,str2)!=NULL) && (strlen(str1)!=strlen(str2)))
        printf("NO");
    else
    printf("YES");
}



return 0;
}

…any idea why?

Answer 1

I think the lines

int len1=strlen(str1)/sizeof(char *);
int len2=strlen(str2)/sizeof(char *);

should read

int len1=strlen(str1);
int len2=strlen(str2);

Then the following should probably be changed

qsort(str1, len1, sizeof(char), cmpr);
qsort(str2, len2, sizeof(char), cmpr);

As we do not have code for qsort I would hazard a guess that the cmpr function is also incorrect.