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.

Then you want a do-while loop.

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

> (valid=0)
Use ==

Also, post a small and complete program which "doesn't work".
There's all sorts of input reasons which can break your code, along with mis-declared variables, broken code logic and the like.

Try to avoid using void main(), use int main().

Actually, it's void menu () :o Whoops.

cin is C++ not C

Quote:

---

this won't work with scanf for some reason

---

maybe you forgot to give pointer to variable

scanf("%d", &menu);