From e6d06cc2787989f019d17ffd841ca8e78be554b2 Mon Sep 17 00:00:00 2001
From: xushiwei <x@goplus.org>
Date: Mon, 6 May 2024 22:31:33 +0800
Subject: [PATCH] demos: hello, concat

---
 README.md                 |  6 ++++--
 _demo/concat/concat.go    | 21 +++++++++++++++++++++
 _demo/genints/gen_ints.go | 18 ++++++++++++++++++
 _demo/hello/hello.go      | 13 +++++++++++++
 _demo/qsort/qsort.go      |  8 ++++++++
 5 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 _demo/concat/concat.go
 create mode 100644 _demo/hello/hello.go

diff --git a/README.md b/README.md
index b4b6e72b..69355b06 100644
--- a/README.md
+++ b/README.md
@@ -36,8 +36,10 @@ go install -v ./...
 
 The `_demo` directory contains our demos (it start with `_` to prevent the `go` command from compiling it):
 
-* [qsort](_demo/qsort): call C function with callback
-* [genints](_demo/genints): closure usage in llgo
+* [hello](_demo/hello/hello.go): call C printf to print `Hello world`
+* [concat](_demo/concat/concat.go): call C fprintf with stderr, and Go variable parameter function
+* [qsort](_demo/qsort/qsort.go): call C function with a callback (eg. qsort)
+* [genints](_demo/genints/genints.go): various forms of closure usage (including C function, recv.method and anonymous function)
 
 ### How to run demos
 
diff --git a/_demo/concat/concat.go b/_demo/concat/concat.go
new file mode 100644
index 00000000..84df62c6
--- /dev/null
+++ b/_demo/concat/concat.go
@@ -0,0 +1,21 @@
+package main
+
+import (
+	"github.com/goplus/llgo/c"
+)
+
+func concat(args ...string) (ret string) {
+	for _, v := range args {
+		ret += v
+	}
+	return
+}
+
+func main() {
+	result := concat("Hello", " ", "World")
+	c.Fprintf(c.Stderr, c.Str("Hi, %s\n"), c.AllocaCStr(result))
+}
+
+/* Expected output (stderr):
+Hi, Hello World
+*/
diff --git a/_demo/genints/gen_ints.go b/_demo/genints/gen_ints.go
index bf8b6d62..e4feeee0 100644
--- a/_demo/genints/gen_ints.go
+++ b/_demo/genints/gen_ints.go
@@ -43,3 +43,21 @@ func main() {
 		c.Printf(c.Str("%d\n"), v)
 	}
 }
+
+/* Posible output:
+16807
+282475249
+1622650073
+984943658
+1144108930
+2
+4
+8
+16
+32
+2
+3
+4
+5
+6
+*/
diff --git a/_demo/hello/hello.go b/_demo/hello/hello.go
new file mode 100644
index 00000000..7437c3e8
--- /dev/null
+++ b/_demo/hello/hello.go
@@ -0,0 +1,13 @@
+package main
+
+import (
+	"github.com/goplus/llgo/c"
+)
+
+func main() {
+	c.Printf(c.Str("Hello world\n"))
+}
+
+/* Expected output:
+Hello World
+*/
diff --git a/_demo/qsort/qsort.go b/_demo/qsort/qsort.go
index 95658371..114bf570 100644
--- a/_demo/qsort/qsort.go
+++ b/_demo/qsort/qsort.go
@@ -15,3 +15,11 @@ func main() {
 		c.Printf(c.Str("%d\n"), v)
 	}
 }
+
+/* Expected output:
+2
+7
+8
+23
+100
+*/