Can you explain what a hashing function is and how it is used in computer systems?

A hash function is an algorithm that transforms input data (such as a string or file) into a fixed-size string or number, called a hash or hash code. The main properties of a hash function:

• Fast computation
• One-wayness (difficult to retrieve original data from the hash)
• Minimization of collisions (different inputs with the same hash)

In computer systems, hash functions are used for:

• Fast data search and comparison (e.g., in hash tables)
• Data integrity verification (checksums)
• Cryptography (storing passwords, digital signatures)

Example in Dart (Flutter) to obtain a hash code of a string:

String text = "example";
int hashCode = text.hashCode;
print(hashCode);

Here, hashCode is an integer value representing the hash of the string.