Question
Answer and Explanation
Creating a short URL programmatically using C involves several key steps. The core idea is to take a long URL, generate a unique short code, and store the mapping between the short code and the long URL. Here's a high-level explanation and an example of how this can be achieved.
1. Generating a Unique Short Code:
One common method is to use a hashing algorithm or a Base62 encoding of an auto-incrementing integer. Base62 is preferred as it produces shorter, human-readable codes consisting of [A-Za-z0-9].
2. Storing the Mapping:
You'll need a database or a key-value store (like Redis) to store the mapping between the short code and the long URL. For simplicity, we will demonstrate using a local file.
3. The C Code Implementation (Illustrative):
The following illustrates a basic approach to generate the short URL. Please note that this is a simplified illustration. You'll need error handling and external library support for network communications for a production system.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
// Simplified Base62 encoding
const char base62 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
// Function to encode a number to Base62
void encode(long long num, char str)
{
int i = 0;
while (num > 0) {
str[i++] = base62[num % 62];
num /= 62;
}
str[i] = '\0';
// Reverse the string
int start = 0;
int end = i - 1;
while (start < end) {
char temp = str[start];
str[start] = str[end];
str[end] = temp;
start++;
end--;
}
}
int main()
{
// Example Long URL
const char longURL = "https://www.example.com/very/long/path";
long long uniqueID = 12345; //Simulating an Auto-Increment ID (From Database)
// Generate short code
char shortCode[10]; // Maximum Length - Adjust based on max expected ID
encode(uniqueID, shortCode);
// Print the results
printf("Long URL: %s\n", longURL);
printf("Short Code: %s\n", shortCode);
return 0;
}
4. Mapping Storage Example:
You would need a persistence layer. This is a highly simplified representation. Imagine your database would store:
Short Code | Long URL
--------- | ---------------------------------
jkV | https://www.example.com/very/long/path
5. Redirection Logic:
Whenever a user accesses the short URL (e.g., `http://yourdomain.com/jkV`), your application would look up the corresponding long URL from the storage and redirect the user to it.
Remember, this explanation and example code are high-level. A complete, production-ready system involves more sophisticated approaches, including using proper URL parsing, validation, and robust data storage. Error Handling also NEEDS to be comprehensive!