Added gnu_regex.c

gnu_regex.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <regex.h>
+
+int main() {
+    regex_t regex;
+
+    regcomp(&regex, "pattern", 0);
+
+    char test_str[] = "This is a pattern example.";
+    regmatch_t pmatch[1];
+
+    if (regexec(&regex, test_str, 1, pmatch, 0) == 0) {
+        printf("Pattern found at position %d.\n", pmatch[0].rm_so);
+    } else {
+        printf("Pattern not found.\n");
+    }
+
+    regfree(&regex);
+
+    return 0;
+}