CODEWITHSUNDEEP
c++inputstructoutput
user4480649
user4480649

Reputation:

How to link a structure with a string key?

I'm working on a stoichiometry calculator in C++. I've stored the properties of each element into data structures. Each data structure is named after the element's symbol. What I want is for the user to be able to type in the symbol of an element and have the program output/use the values in the structure. Example:

User input: He
Program Output: Helium 1 1.00794

How can I do this?

Upvotes: 0

Views: 94

Answers (1)

Lahiru Chandima
Lahiru Chandima

Reputation: 24118

Store data structures in a std::map with symbol as the key. On user input, use std::map::find() to find the symbol in the map and print data in the found data structure 

#include <iostream>
#include <map>


struct element
{
    std::string symbol;
    std::string name;
    double stoichiometry;
};

int main()
{
    element hydrogen;
    hydrogen.symbol = "H";
    hydrogen.name = "Hydrogen";
    hydrogen.stoichiometry = 2;

    element helium;
    helium.symbol = "He";
    helium.name = "Helium";
    helium.stoichiometry = 1.5;

    std::map<std::string, element> elements;
    elements[hydrogen.symbol] = hydrogen;
    elements[helium.symbol] = helium;

    std::string symbol;
    std::cout << "Enter element symbol: ";
    std::cin >> symbol;

    std::map<std::string, element>::iterator it(elements.find(symbol));
    if (it != elements.end())
    {
        std::cout << it->second.name << " " << it->second.stoichiometry << std::endl;
    }
    else
    {
        std::cout << "Symbol " << symbol << " not found";
    }

    return 0;
}

Upvotes: 2

Related Questions