Menu
I am trying to figure out the conversion process for strings to ints. We are doing a program with hashing, in which the key value to be hashed is the name of a state. From my research, it seems like atoi() will not work.
Do I need to break each letter of the word down and individually convert? Do I use ASCII? Am I completely going in the wrong direction?
I am very lost, so ANY information would be fantastic. Thanks!
367
Hashing is the process of transforming any given key or a string of characters into another value. This is usually represented by a shorter, fixed-length value or key that represents and makes it easier to find or employ the original string.
The most commonly used method for hashing integers is called modular hashing: we choose the array size M to be prime, and, for any positive integer key k, compute the remainder when dividing k by M. This function is very easy to compute (k % M, in Java), and is effective in dispersing the keys evenly between 0 and M-1.
In order to create a unique hash from a specific string, it can be implemented using their own string to hash converting function. It will return the hash equivalent of a string. Also, a library named Crypto can be used to generate various types of hashes like SHA1, MD5, SHA256 and many more.
What Is stoi() in C++? In C++, the stoi() function converts a string to an integer value. The function is shorthand for “string to integer,” and C++ programmers use it to parse integers out of strings. The stoi() function is relatively new, as it was only added to the language as of its latest revision (C++11) in 2011.
From here, there are two function to convert string to uint32_t or uint64_t, convert to uint32_t:
inline uint32_t hash_str_uint32(const std::string& str) {
uint32_t hash = 0x811c9dc5;
uint32_t prime = 0x1000193;
for(int i = 0; i < str.size(); ++i) {
uint8_t value = str[i];
hash = hash ^ value;
hash *= prime;
}
return hash;
}
Test:
56
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
