demos: hello, concat

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
 

_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
+*/

_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
+*/

_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
+*/

_demo/qsort/qsort.go

@@ -15,3 +15,11 @@ func main() {
 		c.Printf(c.Str("%d\n"), v)
 	}
 }
+
+/* Expected output:
+2
+7
+8
+23
+100
+*/