C Data Extraction from Text Guide

To extract data from text, you can use string handling functions and a regular expression library in the C language. Below is an example code for extracting numbers.

#include <stdio.h>
#include <string.h>
#include <regex.h>

int main() {
    char text[] = "The price of the product is $99.99";
    char pattern[] = "\\$([0-9]+\\.[0-9]+)";
    
    regex_t regex;
    regmatch_t matches[2];
    
    if(regcomp(&regex, pattern, REG_EXTENDED) != 0) {
        printf("Error compiling regex\n");
        return 1;
    }
    
    if(regexec(&regex, text, 2, matches, 0) == 0) {
        char price[20];
        strncpy(price, text + matches[1].rm_so, matches[1].rm_eo - matches[1].rm_so);
        price[matches[1].rm_eo - matches[1].rm_so] = '\0';
        printf("Price: %s\n", price);
    } else {
        printf("No match found\n");
    }
    
    regfree(&regex);
    
    return 0;
}

In this example, we use regular expressions to match prices ($99.99) in the text. We first compile the regular expression, then use the regexec function to search for matches in the text. If a match is found, we extract the price from the text and print it out. Finally, we release the regular expression object.

Please note that this is just a simple example, actual text data extraction may require more complex regular expressions and processing logic.