C++ string array and bools - c++

Question

I'm currently trying to make a little recipe app. I have made a string array with 10 strings and 10 bools. For example, when I type Cinnemon I want to make the _Cinnemon true. How do I do that?
Also, is this written correctly, or could I make it better? I'm quite new to programming.
Lastly, how can I fix it so it doesn't have anything to say whether it's small letters or big?
Here's the code:
std::cout << "Welcome, type your ingredients " << std::endl;
std::string ingredients[10]{"Cinnemon", "Milk", "Eggs", "Butter", "Tomatoes", "Salt", "Backing Soda", "Suggar", "Chicken", "Honny"};
bool _cinnemon, _milk, _eggs, _butter, _tomatoes, _salt, _backingSoda, _Suggar, _chicken, _honny;
std::string ingredient;
int i = -1;
while (i = -1) {
std::cin >> ingredient;
i++;
while (i < 9)
{
if (ingredient == ingredients[i]){
std::cout << "Type another if you have any more igredients else type Exit" << std::endl;
i++;
} if (ingredient == "Exit" || "exit"){
return 0;
} else{
i++;
}
}
}

Answer 1

Try to map your hard-coded strings into booleans. So you can change them easily.
map<string, bool> m;
m["blah"] = false; // Initialize to false
// Later, you can change it by
m["blah"] = true;
// To look up a value, simply do
if(m.count("blah") && m["blah"]) {
// "blah" is true and do whatever you want to do here
}
As for string comparison ignoring the case, you can write your own function to do that, for example
#include <cctype> // This is where tolower() is defined
bool stringCmpIgnoreCase(string a, string b) {
if(a.length() != b.length())
return false;
for(int i = 0; i < a.length(); i++)
if(tolower(a[i]) != tolower(b[i]))
return false;
return true;
}

Answer 2

I understand that you are learning, so I'll avoid advanced datastructures such as maps and sets, which would be used for a real life application.
My proposed solution just uses an array of boolean. For every indegrients which string is found, I set the boolean flag at the same index. Here is how it works:
std::cout << "Welcome, type your ingredients " << std::endl;
const size_t maxind = 10; // avoid hard coded size !
std::string ingredients[maxind]{"Cinnemon", "Milk", "Eggs", "Butter", "Tomatoes", "Salt", "Backing Soda", "Suggar", "Chicken", "Honny"};
bool hasindegrient[maxind]{}; // make a table to know which one is present
std::string ingredient;
bool stopit = false; // exit requested ?
while (! stopit) {
std::cin >> ingredient;
int i;
for (i=0; i<maxind; i++)
if (ingredient == ingredients[i]){
hasindegrient[i] = true; // <================ set flag of indegrient
break;
}
if (i==maxind) { // here we didn't find it !
if (ingredient == "Exit" || ingredient == "exit")
stopit = true;
else
std::cout << "Indegrient not found !" << std::endl;
if (!stopit)
std::cout << "Type another if you have any more igredients else type Exit" << std::endl;
}
}
for (int i=0; i<10; i++) // display the indegrient list
if (hasindegrient[i])
cout << ingredients[i]<< " ";
cout << endl;
With this approach, each boolean is anonymous: each hasindegrient[i] is either true or false, but has no name. So on its own it doesn't mean anything. But in this programme, if hasindegrient[i] is true, it means that indegrients[i] is in the receipe.
If you want to add some logic where your code interprets the content of the receipe, you could add at the begin an enum that gives a logical name to each index:
enum {IDG_Cinnemon, IDG_Milk, IDG_Eggs, IDG_Butter, IDG_Tomatoes, IDG_Salt, IDG_Backing_Soda, IDG_Suggar, IDG_Chicken, IDG_Honny };
You can understand each element of this enumeration as a constant. As you see, I've followed the same order than in the table of strings. This allows then the writing of code such as:
if (hasindegrient[IDG_Butter]) {
std::cout << "Take care of your cholesterol" << std::endl;
}
Important remarks:
I think you should know some problems of your original code:
while (i = -1) will loop forever, whatever the value of i is. = is the assignement operator (i.e. -1 is copied to i and the value of i is evaluated in condition). This is the most common errors when starting with C/C++: you certainly meant while (i==-1) which is a comparison.
ingredient == "Exit" || "exit" is a valid syntax. But this condition is always true. It does in no way mean "indegrient is either Exit or exit" . For this you'd write ingredient == "Exit" || ingredient =="exit"
your loop structure will not succeed in the search. Especially if the entering of the indegrients doesn't follow the predefined list...

Answer 3

There are different approaches for this task. For example you could use a bool array and an enumeration with names of ingredients that would be used as indices of the array.
You could use std::bitset or std::vector<bool>
You could use an array of pairs std::pair<std::string, bool>.
Also you can use std::map.
Here is a demonstrative program
#include <iostream>
#include <map>
#include <string>
int main()
{
std::map<std::string, bool> ingredients =
{
{ "Cinnemon", false }, { "Milk", false }, { "Eggs",false },
{ "Butter", false }, { "Tomatoes", false }, { "Salt", false },
{ "Backing Soda", false }, { "Suggar", false }, { "Chicken", false },
{ "Honny", false }
};
std::cout << "Welcome, type your ingredients\n" << std::endl;
std::string ingredient;
bool selected = false;
while ( std::getline(std::cin, ingredient ) )
{
if ( ingredient == "Exit" | ingredient == "exit" ) break;
if ( selected = ( ingredients.count( ingredient ) != 0 ) )
{
ingredients[ingredient] = true;
}
else
{
std::cout << "Invalid ingredient." << std::endl;
}
std::cout << "Type another if you have any more igredients else type Exit" << std::endl;
}
if ( selected )
{
std::cout << "You selected ingredients:" << std::endl;
for ( const auto &p : ingredients )
{
if ( p.second ) std::cout << p.first << std::endl;
}
}
return 0;
}
Take into account that you have to use function std::getline instead of operator >> because some ingredient names consist from several words.
Also you should make case insensitive search.