Thread: What loop should I use? While? Do While?

Hey

I am creating a basic currency converter. I have a simple menu but the problem is there is no error control. Here is the code...

Code:

void menu(void)
{
int menu;
int valid = 0;

   printf("	 *****Menu*****\n\n1. Pounds to Euro\n2. Pounds to USD\n3. Pounds to Chinese Yen\n4. Pounds to Australian dollar\n5. Pounds to Canadian dollar\n\n");
	cin >> menu; //this  won't work with scanf for some reason


       switch(menu)
		{
			case 1:
				rate = 1.48018;
            strcpy(convertto, "euros");
            valid = 1;
				break;
			case 2:
				rate = 1.94849;
            strcpy(convertto, "USD");
            valid = 1;
				break;
		  	case 3:
				rate = 15.288;
            strcpy(convertto, "chinese yen");
            valid = 1;
            break;
			case 4:
				rate = 2.4932;
            strcpy(convertto, "australian dollars");
            valid = 1;
            break;
			case 5:
				rate = 2.2014;
            strcpy(convertto, "canadian dollars");
            valid = 1;
            break;
        }
}

Basically, I was the menu to show the first time the App is executed. Then if the user enters a selection higher than 5, they get an error. The menu is shown again ready for them try again.

Any help would be appreciated.

like this?

Code:

do{
   printf("	 *****Menu*****\n\n1. Pounds to Euro\n2. Pounds to USD\n3. Pounds to Chinese Yen\n4. Pounds to Australian dollar\n5. Pounds to Canadian dollar\n\n");
	cin >> menu; //this  won't work with scanf for some reason


       switch(menu)
		{
			case 1:
				rate = 1.48018;
            strcpy(convertto, "euros");
            valid = 1;
				break;
			case 2:
				rate = 1.94849;
            strcpy(convertto, "USD");
            valid = 1;
				break;
		  	case 3:
				rate = 15.288;
            strcpy(convertto, "chinese yen");
            valid = 1;
            break;
			case 4:
				rate = 2.4932;
            strcpy(convertto, "australian dollars");
            valid = 1;
            break;
			case 5:
				rate = 2.2014;
            strcpy(convertto, "canadian dollars");
            valid = 1;
            break;
            }
        }while (valid=0);

I have tried this but it doesn't seem to work