How to read a keyboard number without using "enter" in C++

Question

I want to create a menu in which the user chooses the option 1 to 5, I would like the user to type the number and the program to enter the option without pressing Enter.

Follow an example

#include <iostream>
#include <cstdio>
#include <string>
using namespace std;
struct pessoa {
    int ID;
    string nome [20];
    string tel [20];
};
typedef struct pessoa P;
int main () {
    int vet[10]={0,0,0,0,0,0,0,0,0,0};
    int opc;    
    do{
    cout<<"[0] incluir pessoa"<<endl;
    cout<<"[1] Alterar pessoa"<<endl;
    cout<<"[2] Excluir pessoa"<<endl;
    cout<<"[4] Recuperar pessoa"<<endl;
    cout<<"[5] Sair"<<endl;
    cin>>opc;
    switch (opc){
        case '0':
        break;
        case '1':
        break;  
        case '2':
        break;
        case '3':
        break;
        case '4':
        break;
        case '5':
        break;
        default:
            cout<<"Opção Invalida"<<endl;   
    }
    }while(opc != 5);

    return 0;
}

I want to read the opc without the user needing to enter the Enter and automatically fall into the switch-case.

Answer 1

Basically use the get() of stream input. It is he who picks up a character without waiting for others or a key that ends.

#include <iostream>
#include <string>
using namespace std;

struct Pessoa {
    int ID;
    string nome;
    string tel;
}; //isto provavelmente deveria ser uma classe

int main() {
    Pessoa pessoa; //provavelmente deveria ser inicializado por referência e alocado dinamicamente
    char opc = 'z';
    do {
        cout << "[1] incluir pessoa" << endl;
        cout << "[2] Alterar pessoa" << endl;
        cout << "[3] Excluir pessoa" << endl;
        cout << "[4] Recuperar pessoa" << endl;
        cout << "[0] Sair" << endl;
        opc = cin.get();
        switch (opc) {
            case '0':
                break;
            case '1':
                cout << "1" << endl;
                break;  
            case '2':
                cout << "2" << endl;
            break;
            case '3':
                cout << "3" << endl;
                break;
            case '4':
                cout << "4" << endl;
                break;
            default:
                cout << "Opção Invalida" << endl;
        }
    } while (opc != '0');
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

It’s a shame this code mixes things from C. I gave an organized.