C++ Insights

Source:

#include <iostream>
#include <limits>

int main() {
    // I'd advise against it, but you could at least do:
    using std::cout;
    using std::cin;
    // instead of using namespace std, which I assume you did
    // OR, again, not recommended but at least limit the scope of
    // using namespace std;
    
    int choice;
    
    while (true){  
        cout << "Enter choice: \n";
        // `std::cin` (converts to `bool` indicating errors or lack thereof) - https://en.cppreference.com/w/cpp/io/basic_ios/operator_bool
        // this is the concise version but you can also split it
        // it works because cin returns a reference to self when doing operator >> - also called insertion or put - https://en.cppreference.com/w/cpp/io/basic_istream/operator_gtgt2
        if(!(cin >> choice)) {
            cout << "invalid input! please enter a number\n";
            // clear the error state of this input stream
            // docs: https://en.cppreference.com/w/cpp/io/basic_ios/clear
            cin.clear();
            // ignore all the input that was passed by the user until a certain max limit
            // https://en.cppreference.com/w/cpp/io/basic_istream/ignore
            cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
            // here you can:
            // 1) continue the loop and re-ask for input
            // continue;
            // 2) get out of the loop and end the program (seems that that's what you want to do
            break;
        }
        switch(choice){
           case 1:
                cout << "you picked 1\n";
                break;           
            case 2:
                cout << "you picked 2\n";
                break;
            default:
                cout << "invalid choice\n";
                break;
        }
    }
}

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