add func ptr example and ls script

1 files changed, 41 insertions, 0 deletions

diff --git a/funcptrs.c b/funcptrs.c
new file mode 100644
index 0000000..1d49418
--- /dev/null
+++ b/funcptrs.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void say1(void)
+{
+    printf("hello, world!\n");
+}
+
+void say2(void)
+{
+    printf("hello bro!\n");
+}
+
+/* quite silly function, it is better to return an int and modify a parameter */
+void (*swap_say( void (*current_say)(void) )) (void)
+{
+    if (!current_say)
+        return NULL;
+
+    void (*ret)(void) = NULL;
+
+    if (current_say == &say1)
+        ret = say2;
+    else
+        ret = say1;
+
+    return ret;
+}
+
+int main(int argc, char **argv)
+{
+    void (*say_fptr)(void) = say1;
+    say_fptr();
+
+    /* now modfiy the above func ptr */
+    say_fptr = swap_say(say_fptr);
+    say_fptr();
+
+    return 0;
+}
+