Anagram in C

/*
Write a program in C for anargram
*/ 
#include<stdio.h>

int check(char [], char []);

main()
{
char a[100], b[100];
int flag;

printf("Enter first string\n");
gets(a);

printf("Enter second string\n");
gets(b);

flag = check(a, b);

if ( flag == 1 )
printf("\"%s\" and \"%s\" are anagrams.\n", a, b);
else
printf("\"%s\" and \"%s\" are not anagrams.\n", a, b);

return 0;
}

int check(char a[], char b[])
{
int first[26] = {0}, second[26] = {0}, c = 0;

while ( a[c] != '\0' )
{
first[a[c]-'a']++;
c++;
}

c = 0;

while ( b[c] != '\0' )
{
second[b[c]-'a']++;
c++;
}

for ( c = 0 ; c < 26 ; c++ )
{
if( first[c] != second[c] )
return 0;
}

return 1;
}