From d28188f4d542b07de9bad3e89aa53d8bf1a53a09 Mon Sep 17 00:00:00 2001
From: Pranav Srinivas Kumar <pranav.srinivas.kumar@gmail.com>
Date: Fri, 27 Oct 2023 12:34:57 -0500
Subject: [PATCH] Closes #247

---
 include/argparse/argparse.hpp |  1 +
 test/test_default_value.cpp   | 55 +++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/include/argparse/argparse.hpp b/include/argparse/argparse.hpp
index 9c71697..52e8aeb 100644
--- a/include/argparse/argparse.hpp
+++ b/include/argparse/argparse.hpp
@@ -427,6 +427,7 @@ public:
   }
 
   template <typename T> Argument &default_value(T &&value) {
+    m_num_args_range = NArgsRange{0, m_num_args_range.get_max()};
     m_default_value_repr = details::repr(value);
 
     if constexpr (std::is_convertible_v<T, std::string_view>) {
diff --git a/test/test_default_value.cpp b/test/test_default_value.cpp
index 1a28168..4805f5c 100644
--- a/test/test_default_value.cpp
+++ b/test/test_default_value.cpp
@@ -23,3 +23,58 @@ TEST_CASE("Use a 'string' default value" * test_suite("default_value")) {
     REQUIRE(program.get("--arg") == std::string("string object"));
   }
 }
+
+TEST_CASE("Use a default value with flag arguments" * test_suite("default_value")) {
+
+	argparse::ArgumentParser program("test");
+
+  program.add_argument("-inc_chr", "--include_chromes")
+              .help(std::string{"only process the anchor whose one of the end is contained on the specified "
+                            "chromatin, used ',' to split."})
+              .default_value("all");
+
+  program.add_argument("-l").default_value(false).implicit_value(true);
+  program.add_argument("-o").default_value(false).implicit_value(true);
+
+  program.add_argument("filename");
+
+  SUBCASE("Leading optional argument with default_value") {
+    REQUIRE_NOTHROW(program.parse_args({"test", "-inc_chr", "-lo", "my.log"}));
+    REQUIRE(program.get("-inc_chr") == std::string{"all"});  
+  }
+
+  SUBCASE("Trailing optional argument with default_value") {
+    REQUIRE_NOTHROW(program.parse_args({"test", "-lo", "my.log", "-inc_chr"}));
+    REQUIRE(program.get("-inc_chr") == std::string{"all"});  
+  }
+}
+
+TEST_CASE("Position of the argument with default value") {
+  argparse::ArgumentParser program("test");
+  program.add_argument("-g").default_value("the_default_value");
+  program.add_argument("-s");
+
+  SUBCASE("Arg with default value not passed") {
+    REQUIRE_NOTHROW(program.parse_args({"test", "-s", "./src"}));
+    REQUIRE(program.get("-g") == std::string("the_default_value"));
+    REQUIRE(program.get("-s") == std::string("./src"));
+  }
+
+  SUBCASE("Arg with default value passed last") {
+    REQUIRE_NOTHROW(program.parse_args({"test", "-s", "./src", "-g"}));
+    REQUIRE(program.get("-g") == std::string("the_default_value"));
+    REQUIRE(program.get("-s") == std::string("./src"));
+  }
+
+  SUBCASE("Arg with default value passed before last") {
+    REQUIRE_NOTHROW(program.parse_args({"test", "-g", "-s", "./src"}));
+    REQUIRE(program.get("-g") == std::string("the_default_value"));
+    REQUIRE(program.get("-s") == std::string("./src"));
+  }
+
+  SUBCASE("Arg with default value replaces the value if given") {
+    REQUIRE_NOTHROW(program.parse_args({"test", "-g", "a_different_value", "-s", "./src"}));
+    REQUIRE(program.get("-g") == std::string("a_different_value"));
+    REQUIRE(program.get("-s") == std::string("./src"));
+  }
+}
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