Merge pull request #76 from MuhammadSalah-MS/patch-1

Update printf_argument.c

Author: ohkimur

chapter_1/exercise_1_02/printf_argument.c

@@ -2,6 +2,6 @@
 
 int main(void)
 {
-  printf("hello: \n");
+  printf("hello, world\c");
   return 0;
 }