tasks a-s

Task/Regular-expressions/C/regular-expressions.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <regex.h>
+#include <string.h>
+
+int main()
+{
+   regex_t preg;
+   regmatch_t substmatch[1];
+   const char *tp = "string$";
+   const char *t1 = "this is a matching string";
+   const char *t2 = "this is not a matching string!";
+   const char *ss = "istyfied";
+
+   regcomp(&preg, "string$", REG_EXTENDED);
+   printf("'%s' %smatched with '%s'\n", t1,
+                                        (regexec(&preg, t1, 0, NULL, 0)==0) ? "" : "did not ", tp);
+   printf("'%s' %smatched with '%s'\n", t2,
+                                        (regexec(&preg, t2, 0, NULL, 0)==0) ? "" : "did not ", tp);
+   regfree(&preg);
+   /* change "a[a-z]+" into "istifyed"?*/
+   regcomp(&preg, "a[a-z]+", REG_EXTENDED);
+   if ( regexec(&preg, t1, 1, substmatch, 0) == 0 )
+   {
+      //fprintf(stderr, "%d, %d\n", substmatch[0].rm_so, substmatch[0].rm_eo);
+      char *ns = malloc(substmatch[0].rm_so + 1 + strlen(ss) +
+                        (strlen(t1) - substmatch[0].rm_eo) + 2);
+      memcpy(ns, t1, substmatch[0].rm_so+1);
+      memcpy(&ns[substmatch[0].rm_so], ss, strlen(ss));
+      memcpy(&ns[substmatch[0].rm_so+strlen(ss)], &t1[substmatch[0].rm_eo],
+                strlen(&t1[substmatch[0].rm_eo]));
+      ns[ substmatch[0].rm_so + strlen(ss) +
+          strlen(&t1[substmatch[0].rm_eo]) ] = 0;
+      printf("mod string: '%s'\n", ns);
+      free(ns);
+   } else {
+      printf("the string '%s' is the same: no matching!\n", t1);
+   }
+   regfree(&preg);
+
+   return 0;
+}