update c greet function to return string instead of write to stdout.main

1 files changed, 11 insertions, 3 deletions

diff --git a/greeting.c b/greeting.c
index 1a105e9..0543a0a 100644
--- a/greeting.c
+++ b/greeting.c
@@ -1,11 +1,19 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
-void greet(char *name) {
-  printf("Hello %s\n", name);
+static const char* alias_name = "ALTER_EGO";
+
+char* greet(char* name) {
+  char* alias = getenv(alias_name);
+  char* buffer = (char*)malloc(128);
+  snprintf(buffer, 128, "Hello %s!\n", alias == NULL ? name : alias);
+  return buffer;
 }
 
 int main(int argc, const char *argv[])
 {
-  greet("mo");
+  printf("%s\n", greet("mo"));
   return 0;
 }