feat(solutions): add prefix-suffix/c/function

challenges/prefix-suffix/solutions/c/function/string.c

@@ -0,0 +1,38 @@
+#include "string.h"
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "character.h"
+
+bool string_starts_with(char* string, char* prefix) {
+  size_t string_length = strlen(string);
+  size_t prefix_length = strlen(prefix);
+  bool is_prefix = string_length >= prefix_length;
+  for (size_t index = 0; index < prefix_length && index < string_length && is_prefix; index++) {
+    if (prefix[index] != string[index]) {
+      is_prefix = false;
+    }
+  }
+  return is_prefix;
+}
+
+bool string_ends_with(char* string, char* suffix) {
+  size_t string_length = strlen(string);
+  size_t suffix_length = strlen(suffix);
+  int index_start_of_the_end = string_length - suffix_length;
+  bool is_suffix = true;
+  if (index_start_of_the_end < 0) {
+    is_suffix = false;
+  } else {
+    size_t suffix_index = 0;
+    for (size_t string_index = index_start_of_the_end; string_index < string_length && is_suffix; string_index++) {
+      if (string[string_index] != suffix[suffix_index]) {
+        is_suffix = false;
+      }
+      suffix_index++;
+    }
+  }
+  return is_suffix;
+}