add more functionality

Makefile

@@ -1,4 +1,3 @@
-
 all: build run ## build and run the code
 
 
@@ -14,6 +13,13 @@ run: ## run the code
 clean: ## removes generated directory & files
 	rm -rf bin
 
+create_user_list: ## create a text file that contain all of the system user's
+	awk -F: '{ print $$1}' /etc/passwd >> bin/user.txt
+	@# remove last \n from user.txt file to prevent overprinting Hello in last line
+	truncate -s -1 bin/user.txt
+
+hello_everyone: build create_user_list run ## saying hello to all user
 
 help:
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "%s: %s\n", $$1, $$2}'
+

src/hello_world.c

@@ -1,5 +1,31 @@
 #include <stdio.h>
 
 int main() {
-	puts("Hello World!");
+	FILE *file;
+	if(file = fopen("bin/user.txt", "r"))
+	{
+		char c = fgetc(file);
+		// print Hello for first user
+		if(c != EOF)
+		{
+			printf("Hello ");
+		}
+    		while (c != EOF)
+    		{
+			// print Hello for other user
+			if (c == '\n' && c != '\0')
+			{
+				printf("\nHello ");
+				c = fgetc(file);
+				continue;
+			}
+        		printf("%c",c);
+        		c = fgetc(file);
+    		}
+		fclose(file);
+	}
+	else
+	{
+		puts("Hello World!");
+	}
 }