c++ - Text RPG - Checking For Valid Inputs With Functions - c++

Question

Good evening.
I am currently developing a text RPG. I've been trying to work on a function to vet all my inputs, so that a person would not be able to break my program (or have nothing happen) when they type a string outside of the "accepted" ones for my game. I have this so far, but it is automatically printing "That is not a valid input" for all three of my test cases, even if it is valid. The valid function still executes from the string on top of the "not valid input" prints...
Disclaimer: I have only been studying C++ for about a month, so I am sure the code for this is very procedural, and not in line with OOP. In my class, we have not covered objects/classes, or even vectors/arrays (I have learned these on my own). So my code may be very redundant...
I have included all of my code as to get a full understanding of my program.
My code is as follows:
#include <iostream>
#include <cmath>
#include <vector>
#include <boost/algorithm/string.hpp>
#include <string>
using namespace std;
// This prints all commands used in-game upon input.
void userHelp(string action) {
if (action == "HELP") {
cout << endl;
cout << "Type 'look' to check your surroundings." << endl;
cout << "Type 'location' to print current area and map." << endl;
cout << "Type 'check [item]' to interact with items." << endl;
cout << "Type 'inventory' to check your inventory." << endl;
cout << "Type 'move [north, west, south, east]' to move." << endl;
cout << "Type 'talk [person type]' to begin conversation." << endl;
cout << "Type 'pick up [item]' to pick up items." << endl;
cout << endl;
}
}
void inputVetting(string action) {
while (action = true) {
if (action != "HELP" || action != "LOOK" || action != "LOCATION" || action != "PICK UP BRASS KEY") {
cout << endl;
cout << "That is not a valid input." << endl;
cout << endl;
}
if (action != "CHECK TABLE" || action != "INVENTORY" || action != "TALK GHOUL" || action != "PICK UP KEY") {
cout << endl;
cout << "That is not a valid input." << endl;
cout << endl;
}
if (action != "MOVE NORTH" || action != "MOVE SOUTH" || action != "MOVE EAST" || action != "MOVE WEST") {
cout << endl;
cout << "That is not a valid input." << endl;
cout << endl;
}
}
}
// This prints description lines for the player to check their surroundings of each room upon input.
// This makes it easy to add & change description lines for each room.
void look(string action, int currentRoom) {
if (action == "LOOK") {
if (currentRoom == 1) {
cout << endl;
cout << "There is a table and lamp in the room." << endl;
cout << "There is a ghoulish creature standing in the corner." << endl;
cout << "He seems friendly." << endl;
cout << "There is a door to the north." << endl;
cout << endl;
}
if (currentRoom == 2) {
cout << endl;
cout << "Description line 1." << endl;
cout << "Description line 2." << endl;
cout << "Description line 3." << endl;
cout << "Description line 4." << endl;
cout << endl;
}
}
}
// This prints current player area, and gives visual map of game zone upon input.
void location(string action, int currentRoom) {
if (action == "LOCATION") {
if (currentRoom == 1) {
cout << endl;
cout << "You are currently in room one." << endl;
cout << "|-----------------------------|" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "| T E S T 1 |" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "|-----------------------------|" << endl;
cout << endl;
}
if (currentRoom == 2) {
cout << endl;
cout << "You are currently in room two." << endl;
cout << "|-----------------------------|" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "| T E S T 2 |" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "| |" << endl;
cout << "|-----------------------------|" << endl;
cout << endl;
}
}
}
// This provides interactions with objects placed according to each area in the game zone upon input.
void checkItem(string action, int currentRoom) {
if (currentRoom == 1) {
if (action == "CHECK TABLE") {
cout << endl;
cout << "Description line A." << endl;
cout << "Description line B." << endl;
cout << "Do you want to open the drawer?" << endl;
cout << "(1) Yes\n(2) No" << endl;
cout << endl;
string choice;
cin >> choice;
boost::to_upper(choice);
if (choice == "1" || choice == "YES") {
cout << endl;
cout << "You open the drawer." << endl;
cout << "There is a brass key inside." << endl;
cout << endl;
} else if (choice == "2" || choice == "NO") {
cout << endl;
cout << "You leave the drawer alone." << endl;
cout << endl;
}
}
}
}
//This simple function allows user to pick up the key in the first game area.
void pickUpKey(string action, int currentRoom, vector<string>& inventory) {
if (currentRoom == 1) {
if (action == "PICK UP KEY" || action == "PICK UP BRASS KEY") {
cout << endl;
cout << "You have picked up the brass key." << endl;
cout << "It is now in your inventory." << endl;
cout << endl;
inventory.push_back("Brass Key");
}
}
}
// This prints description lines for the first game area.
void firstRoom() {
cout << endl;
cout << "You awake in a dark cabin-like room." << endl;
cout << "(Type 'help' for commands)" << endl;
}
//This prints description lines for the second game area.
void secondRoom() {
cout << "Description line 1." << endl;
cout << "Description line 2." << endl;
cout << "Description line 3." << endl;
cout << "Description line 4." << endl;
}
// This helps player move around the first area upon input.
// I've split up the movements into functions per room, for easier altering/flow
void movePlayerFirstRoom(string action, int& currentRoom, vector<string>& inventory) {
if (action == "MOVE NORTH" && currentRoom == 1) {
std::vector<string>::iterator it;
it = find(inventory.begin(), inventory.end(), "Brass Key");
if (it != inventory.end()) {
currentRoom = 2;
cout << endl;
} else {
cout << endl;
cout << "The door is locked!" << endl;
cout << endl;
}
}
if (action == "MOVE SOUTH" && currentRoom == 1) {
cout << endl;
cout << "You can't walk past a wall!" << endl;
cout << endl;
}
if (action == "MOVE EAST" && currentRoom == 1) {
cout << endl;
cout << "You can't walk past a wall!" << endl;
cout << endl;
}
if (action == "MOVE WEST" && currentRoom == 1) {
cout << endl;
cout << "You can't walk past a wall!" << endl;
cout << endl;
}
}
// This helps player move around the second area upon input.
void movePlayerSecondRoom(string action, int& currentRoom) {
if (action == "MOVE NORTH" && currentRoom == 2) {
cout << endl;
cout << "You can't walk past a wall!" << endl;
cout << endl;
}
if (action == "MOVE SOUTH" && currentRoom == 1) {
cout << endl;
cout << "Juub closed the door behind him." << endl;
cout << "You can no longer go that way." << endl;
cout << endl;
}
if (action == "MOVE EAST" && currentRoom == 1) {
cout << "You can't walk past a wall!" << endl;
cout << endl;
}
if (action == "MOVE WEST" && currentRoom == 1) {
cout << "You can't walk past a wall!" << endl;
cout << endl;
}
}
// This provides a for loop to display the items in player's inventory, used in checkInventory.
void listInventory(vector<string> inventory) {
for (auto i : inventory) {
cout << ":: " << i << endl;
}
}
// This prints out a player's inventory upon input.
void checkInventory(string action, vector<string>& inventory) {
if (action == "INVENTORY") {
cout << endl;
cout << "Your inventory contains: " << endl;
listInventory(inventory);
cout << endl;
}
}
// This provides basic mechanics for combat against enemies.
// void attackEnemy;
// This is the dialogues for NPC 1.
void npcOne(string action) {
if (action == "TALK GHOUL") {
string choice;
cout << endl;
cout << "Ah, hello." << endl;
cout << "I haven't seen anyone around here in a long time." << endl;
cout << "Name's Juub. I've been down here trying to find treasure." << endl;
cout << "Problem is, I haven't found anything..." << endl;
cout << "... but I have found a monster." << endl;
cout << "Actually, that's why I'm in this room." << endl;
cout << "A corrupted spirit chased me into here." << endl;
cout << "I was lucky enough to lock myself in, otherwise I'd surely be dead." << endl;
cout << "But... now, that you're here..." << endl;
cout << "Mind helping me out?" << endl;
cout << endl;
cout << "Do you want to help Juub kill the monster?" << endl;
cout << "(1) Yes\n(2) No" << endl;
cout << endl;
cin >> choice;
boost::to_upper(choice);
cout << endl;
if (choice == "1" || "YES") {
cout << "Excellent." << endl;
cout << "I wish I could be of help, but I got a bad arm." << endl;
cout << "Got shot in the Great War by a phaser rifle." << endl;
cout << "Come back with his essence, and I'll give you a reward." << endl;
cout << "... oh, yeah. The key to the door is somewhere in this room." << endl;
cout << endl;
} else if (choice == "2" || "NO") {
cout << "Eh, figures..." << endl;
cout << "Can never trust humanoids, anyway." << endl;
cout << endl;
}
}
}
// This is a small function to get the user's name, used in gameIntro.
void getName() {
cout << "Please enter your name." << endl;
cout << endl;
string name;
cin >> name;
cout << endl;
cout << "Welcome, " << name << ". Enjoy the game!" << endl;
}
// This is the introduction prompt of the game.
// This gives players the option to play or quit the game, then sets player's name.
void gameIntro() {
cout << endl;
cout << "==============================" << endl;
cout << "Welcome to *Love Pits*" << endl;
cout << "==============================" << endl;
cout << endl;
getName();
cout << endl;
cout << "..." << endl;
cout << "..." << endl;
cout << "..." << endl;
// cout << string(60, '\n'); <-- This is an attempt to try and clear screen, not sure if I want to do this.
}
int main() {
vector<string> inventory;
int currentRoom;
string action;
inventory.push_back("Rusted Dagger");
while (true) {
gameIntro();
currentRoom = 1;
firstRoom();
cout << endl;
// All possible actions/interactions within room one.
while (currentRoom == 1) {
if (currentRoom != 1) {
break;
}
getline(cin, action);
boost::to_upper(action);
//Provides all possible actions for player.
checkInventory(action, inventory);
checkItem(action, currentRoom);
userHelp(action);
look(action, currentRoom);
location(action, currentRoom);
movePlayerFirstRoom(action, currentRoom, inventory);
npcOne(action);
pickUpKey(action, currentRoom, inventory);
inputVetting(action);
}
secondRoom();
cout << endl;
// All possible actions/interactions in game area two.
while (currentRoom == 2) {
if (currentRoom != 2) {
break;
}
getline(cin, action);
boost::to_upper(action);
// Provides all possible actions for player.
checkInventory(action, inventory);
checkItem(action, currentRoom);
userHelp(action);
look(action, currentRoom);
movePlayerSecondRoom(action, currentRoom);
location(action, currentRoom);
}
}
}
Can anyone help me figure out why my vetting function isn't working? Or, if better, what are some things and places I can do them where I can vet the input properly, so the user can only type in commands that will work within the program, otherwise I print out something like "That is not a valid input"? Thanks for any help! I am just trying to improve as much as possible.

Answer 1

Check your logic. How we speak English does not translate into how we apply boolean logic to an if statement.
if (action != "HELP" || action != "LOOK" || action != "LOCATION" || action != "PICK UP BRASS KEY")
Let's say that you input "LOOK". Here is what that entire if breaks down to:
if (action != "HELP" || // true
action != "LOOK" || // false
action != "LOCATION" || // true
action != "PICK UP BRASS KEY") // true
Since you apply || (or) to all of those tests, all that is required is that one of those tests becomes true for the whole thing to be true. So that entire if becomes true, and thus enters the if error block.
The fix is to use && (and):
if (action != "HELP" && action != "LOOK" && action != "LOCATION" && action != "PICK UP BRASS KEY")
Now let's see how this goes if "LOOK" is entered:
if (action != "HELP" && // true
action != "LOOK" && // false
action != "LOCATION" && // true
action != "PICK UP BRASS KEY") // true
Now, if any of those conditions is false, then the whole if becomes false, thus does not enter the error block.
Compare now if "ABC" is entered:
if (action != "HELP" && // true
action != "LOOK" && // true
action != "LOCATION" && // true
action != "PICK UP BRASS KEY") // true
Thus "ABC" doesn't match any of the choices, thus the if becomes true and enters the error block.
A further point -- if you had more entries to check, having an endless if statement does not scale very well. Consider putting the words in a table and do a lookup, i.e. an unordered_set or similar, and just use find() to see if the entry is in the table.