Validation so that the program only allows entry of numbers

Hi, could someone help me with my program. I have my program that is from a restaurant where you have to enter what you will eat for lunch, drink and dessert. The program gives you the invoice-like quantities and prices, all right there, the problem is that I need that when you enter any character that is not a number the program allows you to re-select the correct option for each option. If anyone could help me with this I would greatly appreciate it.

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#include <iostream>
using namespace std;
 
const float torta=20000;
const float helado=15000;
const float oferta_postre=8000;
const float sopa=15000;
const float arroz_pollo=25000;
const float pasta_bolona=35000;
const float oferta_almuerzo=15000;
const float jarra_jugo=15000;
const float vaso_jugo=5000;
const float jarra_agua=10000;
const float vaso_agua=3000;
float total = 0;
int continuar = 0;
int acum_op1 = 0;
int acum_op2 = 0;
int acum_op3 = 0;
int acum_op4 = 0;
int acum_op5 = 0;
int acum_op6 = 0;
int acum_op7 = 0;
int acum_op8 = 0;
int acum_op9 = 0;
int acum_op10 = 0;
int acum_op11 = 0;
int opcion=0;
 
void pedido(int op){
	int cantidad = 0;
	cout<<"Ingrese la cantidad a pedir:  "<<endl;
	cin>>cantidad;
	switch(op)
	{
		case 1:
			total = total + (sopa * cantidad);
			acum_op1 = acum_op1 + cantidad;
			break;
		case 2:
			total = total + (arroz_pollo * cantidad);
			acum_op2 = acum_op2 + cantidad;
			break;
		case 3:
			total = total + (pasta_bolona * cantidad);
			acum_op3 = acum_op3 + cantidad;
			break;
		case 4:
			total = total + (oferta_almuerzo * cantidad);
			acum_op4 = acum_op4 + cantidad;
			break;
		case 5:
			total = total + (jarra_jugo * cantidad);
			acum_op5 = acum_op5 + cantidad;
			break;
		case 6:
			total = total + (vaso_jugo * cantidad);
			acum_op6 = acum_op6 + cantidad;
			break;
		case 7:
			total = total + (jarra_agua * cantidad);
			acum_op7 = acum_op7 + cantidad;
			break;
		case 8:
			total = total + (vaso_agua * cantidad);
			acum_op8 = acum_op8 + cantidad;
			break;
		case 9:
			total = total + (torta * cantidad);
			acum_op9 = acum_op9 + cantidad;
			break;
		case 10:
			total = total + (helado * cantidad);
			acum_op10 = acum_op10 + cantidad;
			break;
		case 11:
			total = total + (oferta_postre * cantidad);
			acum_op11 = acum_op11 + cantidad;
			break;
		default:
			cout<<"Ingreso una opción invalida"<<endl;
			break;
	}
}
 
void submenu(int op){
	int plato = 0;
	if(op == 1)
	{
		cout <<"En el almuerzo hay:  "<<endl<<endl;
		cout <<"1) Sopa = 15000 "<<endl;
		cout <<"2) Arroz con Pollo = 25000 "<<endl;
		cout <<"3) Pasta Boloñesa = 35000 "<<endl;
		cout <<"4) OFERTA Especial = 15000 (1 bebida y Arroz con Salsa) "<<endl<<endl;
		cin>>plato;
		if(plato >= 1 && plato <= 4){
			pedido(plato);
		}
		else{
			cout<<"Ingreso una opción invalida"<<endl;
			submenu(op);
		}
	}
	else if(op == 2)
	{
		cout <<"De bebida tenemos:  "<<endl<<endl;
		cout <<"5) Jarra de Jugo = 15000 "<<endl;
		cout <<"6) Vaso de Jugo = 5000 "<<endl;
		cout <<"7) Jarra de Agua = 10000 "<<endl;
		cout <<"8) Vaso de Agua = 3000 "<<endl;
		cin>>plato;
		if(plato >= 5 && plato <= 8){
			pedido(plato);
		}
		else{
			cout<<"Ingreso una opción invalida"<<endl;
			submenu(op);
		}
	}
	else{
		cout <<" De postre hay:  "<<endl<<endl;
		cout <<"9)torta = 20000 "<<endl;
		cout <<"10)helado = 15000 "<<endl;
		cout <<"11)OFERTA ESPECIAL = 8000 (1 cafe y galletas dulces) "<<endl<<endl;
		cin>>plato;
		if(plato >= 9 && plato <= 11){
			pedido(plato);
		}
		else{
			cout<<"Ingreso una opción invalida"<<endl;
			submenu(op);
		}
	}
}
 
 
void menu(){
	cout<<"1) Almuerzo"<<endl;
	cout<<"2) Bebida"<<endl;
	cout<<"3) Postre"<<endl;
	cin>>opcion;
 
	switch(opcion){
		case 1:
			submenu(1);
			break;
		case 2:
			submenu(2);
			break;
		case 3:
			submenu(3);
			break;
		default:
			cout<<"Ingreso una opción invalida"<<endl;
			menu();
			break;
	}
	while(continuar != 1 and continuar != 2){
		cout<<"¿Desea pedir algo más? Si=1;No=2"<<endl;
		cin>>continuar;
	}
	if(continuar==1){
		continuar=0;
		menu();
	}
	else{
		cout<<"\n*** PEDIDO *** "<<endl<<endl;
 
		if(acum_op1 >0 ){
			cout<<acum_op1<<" Sopa"<<endl<<endl;
		}
		if(acum_op2 >0 ){
			cout<<acum_op2<<" Arroz con Pollo"<<endl<<endl;
		}
		if(acum_op3 >0 ){
			cout<<acum_op3<<" Pasta Boloñesa"<<endl<<endl;
		}
		if(acum_op4 >0 ){
			cout<<acum_op4<<" OFERTA Especial (1 bebida y Arroz con Salsa)"<<endl<<endl;
		}
		if(acum_op5 >0 ){
			cout<<acum_op5<<" Jarra de Jugo"<<endl<<endl;
		}
		if(acum_op6 >0 ){
			cout<<acum_op6<<" Vaso de Jugo"<<endl<<endl;
		}
		if(acum_op7 >0 ){
			cout<<acum_op7<<" Jarra de Agua"<<endl<<endl;
		}
		if(acum_op8 >0 ){
			cout<<acum_op8<<" Vaso de Agua"<<endl<<endl;
		}
		if(acum_op9 >0 ){
			cout<<acum_op9<<" Torta"<<endl<<endl;
		}
		if(acum_op10 >0 ){
			cout<<acum_op10<<" Helado"<<endl<<endl;
		}
		if(acum_op11 >0 ){
			cout<<acum_op11<<" OFERTA ESPECIAL (1 cafe y galletas dulces)"<<endl<<endl;
		}
		cout<<"Total a Pagar:  "<<total<<endl<<endl;
	}
}
 
int main(int argc, char *argv[]) {
	cout<<"*** BIENVENIDOS AL RESTAURANTE BONIN ***"<<endl<<endl<<endl;
	cout<<"  ** ¿ QUE DESEA ORDENAR ? ** "<<endl<<endl;
	menu();
	return 0;
Last edited on
Did you know you can putcin >> variable into the condition of a while loop?

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while(cin >> variable) {
    // If we're here, we read into variable successfully. Do something with it!
}


It's a handy little pattern. However, here, you want to do something repeatedly so long as the read failed. That would look more like:

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while( !( cin >> variable ) ) {
    //TODO: Print a message complaining about the input.
    cin.clear(); //Reset the error flags for cin so that we can try again.
}


You have a lot of cin >> someinteger lines, so you might want to consider writing a function that returns an int and does that whole while loop for you.

Good luck!

-Albatross
thanks for the reply. and if I deal with the ctype.h library (isalpha isdigit) how would it be? to validate the options and the menu in this case.
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