Hash test

#include <iostream>
#include <map>

using namespace std;

uint64_t hashf1(const char *str) // XOR version
{
    uint64_t hash = 5381;
    int c;

    while (c = *str++)
    hash = ((hash << 5) + hash) ^ c; /* hash * 33 ^ c */

    return hash;
}
uint64_t hashf2(const char *str) // + version
{
    uint64_t hash = 5381;
    int c;

    while (c = *str++)
    hash = ((hash << 5) + hash) + c; /* hash * 33 + c */

    return hash;
}


void EvaluateHash(uint64_t (*bad_hash)(const char *)){
    std::map<uint64_t, std::string> hashes;
    const char *charset="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    for(const char *i=charset; *i!=0; ++i){
        for(const char *j=charset; *j!=0; ++j){
            char str[3]={*i,*j,0};

            uint64_t hash=bad_hash(str);
            if(hashes.count(hash)){
                std::cout<<str<<","<<hashes[hash]<<" to "<<hash<<std::endl;
            }else{
                hashes[hash]=std::string(str);
            }
        }
    }
    std::cout<<"*************************************************************************************************************"<<std::endl;
}

int main()
{
    //cout << "Hello world!" << bad_hash("g5")<<","<<bad_hash("as")<<endl;
    std::cout<<"hashf1:"<<std::endl;
    EvaluateHash(hashf1);
    std::cout<<"hashf2:"<<std::endl;
    EvaluateHash(hashf2);

    std::cout<<"demo for how longer strings collide"<<std::endl;


    // observe what happens when your hash function is linear: you can get a collision in a longer string
    std::cout<<hashf2("Some longer string bA bla bla")<<std::endl;
    std::cout<<hashf2("Some longer string ab bla bla")<<std::endl;

    std::cout<<hashf1("Some longer string cb bla bla")<<std::endl;
    std::cout<<hashf1("Some longer string bC bla bla")<<std::endl;
    return 0;
}