Added check for whether the destination user exists

Makefile

@@ -1,5 +1,5 @@
 EXEC_FILE=main
-TARGETS=$(EXEC_FILE).o message.o user.o message_helpers.o file_helpers.o
+TARGETS=$(EXEC_FILE).o message.o user.o message_helpers.o file_helpers.o stack.o
 CFLAGS=
 
 
@@ -14,6 +14,7 @@ message.o: message.c
 user.o: user.c
 message_helpers.o: message_helpers.c
 file_helpers.o: file_helpers.c
+stack.o: stack.c
 $(TARGETS):
 	gcc $(CFLAGS) -c -o $@ $^
 

main.c

@@ -20,6 +20,8 @@
 User** create_user_list(char* filename);
 void sigint_handler(int dummy);
 User* fetch_user(char* username);
+int user_to_index(User* user);
+bool user_equals(User* this, User* other);
 
 User** users;
 int num_users;
@@ -120,10 +122,17 @@ int main() {
 					}	
 
 					printf("Your message is: %s\n",message_string);
-					Message message = new_message(message_string,from_user[i],to_user[i]);
 
+					if (user_to_index(to_user[i]) < 0) {
+						printf("Recipient user does not exist!\n");
+						return -20;
+					}
+
+					Message* message = new_message(message_string,from_user[i],to_user[i]);
 					stack_push( message_stack[user_to_index(to_user[i])],message );
 
+					printf("Message has been pushed onto stack for %s\n",to_user[i]->username);
+
 					
 
 					close(conn_sockets[i]);					
@@ -205,7 +214,7 @@ User* fetch_user(char* username) {
 }
 
 int user_to_index(User* user) {
-	int index = 0;
+	int index = -1;
 	for (int i=0;i < num_users; i++) {
 		if (user_equals(users[i],user) == true) {
 			index = i;

message.c

@@ -4,14 +4,22 @@
 #include <time.h>
 #include "message.h"
 
-Message new_message(char* string, User from, User to) {
+Message* new_message(char* string, User* from, User* to) {
-	Message new_message;
+	Message* new_message;
 
-	new_message.text = malloc((strlen(string)+1)*sizeof(char));
+	new_message = malloc(sizeof(Message));
-	strcpy(new_message.text,string);
+	new_message->text = malloc((strlen(string)+1)*sizeof(char));
+	strcpy(new_message->text,string);
 	
-	new_message.sender = from;
+	new_message->sender = malloc(sizeof(User));
-	new_message.recipient = to;
+	new_message->recipient = malloc(sizeof(User));
+
+	memcpy(new_message->sender, from, sizeof(User));
+	memcpy(new_message->recipient, to, sizeof(User));
+
+
+//	*(new_message->sender) = *from;
+//	*(new_message->recipient) = *to;
 
 	time_t rawtime;
 	struct tm timeinfo;
@@ -19,7 +27,7 @@ Message new_message(char* string, User from, User to) {
 	time(&rawtime);
 	timeinfo = *localtime(&rawtime);
 
-	new_message.timeinfo = timeinfo;
+	new_message->timeinfo = timeinfo;
 
 	return new_message;	
 

message.h

@@ -11,10 +11,10 @@ typedef struct Message_s Message;
 struct Message_s {
 	char* text;
 	struct tm timeinfo;
-	User sender;
+	User* sender;
-	User recipient;
+	User* recipient;
 };
 
-Message new_message(char* text,User from,User to);
+Message* new_message(char* text,User* from,User* to);
 
 #endif