Here is below the code that I need and have to understand what it does..Give me your ideas about it please..
str1 = "ABCD"
str2 = "ACDS"
str3 = "KLMN"
int getUnique(char str1[],char str2[],char str3[],char arr[])
{
int i,k,temp[26];
for(i = 0 ; i<26 ; temp[i]=0 , ++i);
for(i = 0 ; str1[i] ; ++i)
temp[str1[i] - 'A'] = 1;
for(i = 0 ; str2[i] ; ++i)
temp[ str2[i] - 'A'] = 1 ;
for(i = 0 ; str3[i] ; ++i)
temp[str3[i] - 'A'] = 1;
for(i = k = 0 ; i<26 ; ++i)
if(temp[i])
arr[k++] = i + 'A';
arr[k] = '\0';
return k;
}