Homework SourseUsing C write a function that creates a 32bit hash file Plea
Using C++ write a function that creates a 32-bit hash file. Please represent the 32 bits in hexadecimal.
-read the txt from the users keyboard
-Set the hash to all ones
-In a circular manner shift the bit pattern in the hash to the right 6 positions.
-XOR the new byte read from the file with the most significant byte (the leftmost) of the hash.
-print the hash on the screen
Solution
#include \"GeneralHashFunctions.h\"
unsigned int RSHash(const std::string& str)
{
unsigned int b = 378551;
unsigned int a = 63689;
unsigned int hash = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = hash * a + str[i];
a = a * b;
}
return hash;
}
/* End Of RS Hash Function */
unsigned int JSHash(const std::string& str)
{
unsigned int hash = 1315423911;
for(std::size_t i = 0; i < str.length(); i++)
{
hash ^= ((hash << 5) + str[i] + (hash >> 2));
}
return hash;
}
/* End Of JS Hash Function */
unsigned int PJWHash(const std::string& str)
{
unsigned int BitsInUnsignedInt = (unsigned int)(sizeof(unsigned int) * 8);
unsigned int ThreeQuarters = (unsigned int)((BitsInUnsignedInt * 3) / 4);
unsigned int OneEighth = (unsigned int)(BitsInUnsignedInt / 8);
unsigned int HighBits = (unsigned int)(0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth);
unsigned int hash = 0;
unsigned int test = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = (hash << OneEighth) + str[i];
if((test = hash & HighBits) != 0)
{
hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits));
}
}
return hash;
}
/* End Of P. J. Weinberger Hash Function */
unsigned int ELFHash(const std::string& str)
{
unsigned int hash = 0;
unsigned int x = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = (hash << 4) + str[i];
if((x = hash & 0xF0000000L) != 0)
{
hash ^= (x >> 24);
}
hash &= ~x;
}
return hash;
}
/* End Of ELF Hash Function */
unsigned int BKDRHash(const std::string& str)
{
unsigned int seed = 131; // 31 131 1313 13131 131313 etc..
unsigned int hash = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = (hash * seed) + str[i];
}
return hash;
}
/* End Of BKDR Hash Function */
unsigned int SDBMHash(const std::string& str)
{
unsigned int hash = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = str[i] + (hash << 6) + (hash << 16) - hash;
}
return hash;
}
/* End Of SDBM Hash Function */
unsigned int DJBHash(const std::string& str)
{
unsigned int hash = 5381;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = ((hash << 5) + hash) + str[i];
}
return hash;
}
/* End Of DJB Hash Function */
unsigned int DEKHash(const std::string& str)
{
unsigned int hash = static_cast<unsigned int>(str.length());
for(std::size_t i = 0; i < str.length(); i++)
{
hash = ((hash << 5) ^ (hash >> 27)) ^ str[i];
}
return hash;
}
/* End Of DEK Hash Function */
unsigned int BPHash(const std::string& str)
{
unsigned int hash = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash = hash << 7 ^ str[i];
}
return hash;
}
/* End Of BP Hash Function */
unsigned int FNVHash(const std::string& str)
{
const unsigned int fnv_prime = 0x811C9DC5;
unsigned int hash = 0;
for(std::size_t i = 0; i < str.length(); i++)
{
hash *= fnv_prime;
hash ^= str[i];
}
return hash;
}
/* End Of FNV Hash Function */
unsigned int APHash(const std::string& str)
{
unsigned int hash = 0xAAAAAAAA;
for(std::size_t i = 0; i < str.length(); i++)
{
hash ^= ((i & 1) == 0) ? ( (hash << 7) ^ str[i] * (hash >> 3)) :
(~((hash << 11) + (str[i] ^ (hash >> 5))));
}
return hash;
}
/* End Of AP Hash Function */
