I am making a program which consists of making a menu to register and delete products from a store, I am just designing the menu with a switch, everything works fine up to there, the problem is that when I enter something other than a number as data ( letter or symbol) the console goes crazy; all the text starts to blink and it won't let me do anything (as if it was in a loop) and I have to close it.

Is there any way to avoid this? So when I enter a letter or symbol, it automatically detects it as invalid and shows me the message without the console going crazy?

By the way, I use Visual Studio.

Thanks in advance :)

#include<iostream>
#include<locale.h>

using namespace std;

int main()
{
   
    int opc;

    cout << "                WELCOME TO THE STORE \"Happy Shopping\" ";
    cout << endl;
    

    cout << "\n1.- Create Order.";
    cout << "\n2.- Delate Order.";
    cout << "\n3.- list of orders created.";
    cout << "\n4.- Exit";
    cout << endl;
    cout << "\n¿what do you want to do?: "; cin >> opc;

    switch (opc)
    {

    case 1:cout << "\nCreate Order"; break;
    case 2:cout << "\nDelate Order"; break;
    case 3: cout << "\nlist of orders created"; break;
    case 4:exit(EXIT_SUCCESS);
    default:
        
        if ((opc != 1) && (opc != 2) && (opc != 3) && (opc != 4))
        {

            system("cls");

                cout << "the option entered is not valid, try again";
                return main();


        }
    }
}

CodePudding user response：

Maybe don't return main?

switch (opc)
{

case 1:cout << "\nCreate Order"; break;
case 2:cout << "\nDelate Order"; break;
case 3: cout << "\nlist of orders created"; break;
case 4:exit(EXIT_SUCCESS);
default:
    system("cls");
    cout << "the option entered is not valid, try again";
}

CodePudding user response：

If you make opc a string and take input as a string, you can manually check if the string is a number like so:

cin >> opc;
if (!isdigit(opc[0]) // since you're dealing with single-digit numbers, this should be fine
{
  cout << "You didn't enter a number!\n";
  // Any other error handling
}

isdigit is a function located in the cctype header file, so you should add #include <cctype> at the beginning of the file.

After this, you can convert opc to an integer with stoi():

int opnum = stoi(opc);
// opnum is now the number, write the rest of the code such that it uses opnum

CodePudding user response：

As already said, you should not return main(). You may use a loop by testing your input for instance (surely one of the many solutions that may exist).

Also, you do not need the portion of code below :

 // you do not need the if as you are already in the case !=1,2,3, or 4
 if ((opc != 1) && (opc != 2) && (opc != 3) && (opc != 4))

I provided you with an attempt, taken from your code, that may help to improve your code. There might still be some bugs but it is a good starting point

#include<iostream>
#include<locale.h>

int main()
{

    int opc=0;
    std::string input;

    std::cout << "                WELCOME TO THE STORE \"Happy Shopping\" ";
    std::cout << std::endl;
    // first display
    std::cout << "\n1.- Create Order.";
    std::cout << "\n2.- Delate Order.";
    std::cout << "\n3.- list of orders created.";
    std::cout << "\n4.- Exit";
    std::cout << std::endl;
    std::cout << "\n¿what do you want to do?: "; //cin >> opc;

    std::cin >> input;

    while ( input.length() > 0 )
    {
        // if we enter a string of more than length 1


        try
        {
            opc = std::stoi( input );

        }
        catch (...)
        {
            // mainly if the converted argument is not a number =>std::invalid_argument
            std::cout << "invalid value " << opc << std::endl;
        }
        std::cout << "you entered the value " << opc << std::endl;

        switch (opc)
        {

        case 1:
            std::cout << "\nCreate Order";
            break;
        case 2:
            std::cout << "\nDelate Order";
            break;
        case 3:
            std::cout << "\nlist of orders created";
            break;
        case 4:
            exit(EXIT_SUCCESS);
        default:
            // you do not need the if as you are already in the case !=1,2,3, or 4
            //if ((opc != 1) && (opc != 2) && (opc != 3) && (opc != 4))
            //{
            system("cls");
            // if you type things other than
            std::cout << "\n1.- Create Order.";
            std::cout << "\n2.- Delate Order.";
            std::cout << "\n3.- list of orders created.";
            std::cout << "\n4.- Exit";
            std::cout << std::endl;
            std::cout << "\n¿what do you want to do?: "; //cin >> opc;
        }

        std::cin >> input;

    }
}