Switches and default

[arya6000]

Hello

I wrote this program:

int selection;

printf("1.)   Integer to Binary converter\n");
printf("2.)   Fibonacci generator\n");
printf("999.) Exit\n");
printf("Enter selection ---> ");
scanf("%d", &selection);

switch (selection){

  case 1:
   printf("You selected 1\n");
   break;

  case 2:
   printf("You selected 2\n");
   break;

  case 999:
   printf("Goodbye\n");
   break;

  default:
   printf("Wronge selection\n");
   break;

                   }

This program needs a lot more work to be finished, but how can I make it that when the default switch gets selected the top menu gets repeated until that the user selects 1,2, or 999?

[jimzy]

You could put part of the code that's displaying menu-info into separate function, eg.

void printMenu()
{
   printf("1.)   Integer to Binary converter\n");
   printf("2.)   Fibonacci generator\n");
   printf("999.) Exit\n");
   printf("Enter selection ---> ");
}

and later on ask user for input in while ( 1 ) loop. If it reaches default in switch, you simply call printMenu().

default:
   printf("Wronge selection\n");
   printMenu();

[foxman]

One way to resolve your problem is changing your piece of code for something like this

int i;
// ...

do
{
    printf("1.)   Integer to Binary converter\n");
    printf("2.)   Fibonacci generator\n");
    printf("999.) Exit\n");

    printf("Enter selection ---> ");
    i = scanf("%d", &selection);
    while (getchar() != '\n');                   // flush the input buffer
} while (i != 1 && selection != 1 && selection != 2 && selection != 999);

// you put the switch instruction here
// note that selection WILL be 1, 2 or 999

[arya6000]

I changed my program to :

#include <stdio.h>

int printMenu(int menu)
{
   printf("1.)   Integer to Binary converter\n");
   printf("2.)   Fibonacci generator\n");
   printf("999.) Exit\n");
   printf("Enter selection ---> ");
   scanf("%d", &menu);

   return menu;
}

main(){

int selection;

selection = printMenu(selection);

switch (selection){

  case 1:
   printf("You selected 1\n");
   break;

  case 2:
   printf("You selected 2\n");
   break;

  case 999:
   printf("Goodbye\n");
   break;

  default:
   printf("Wronge selection\n");
   break;
   printMenu();
                   }

    }

but by putting

printMenu();

in the default section of the switch it gives compile errors. How can I call the menu from the default switch?

[Salem]

You mean something along the lines of "unreachable code", because you put the function call AFTER the break statement?

Or something else (be specific!).

[arya6000]

You mean something along the lines of "unreachable code", because you put the function call AFTER the break statement?

Or something else (be specific!).

oops I never realized its after break. after putting "printMenu();" in the default section of the switch I get compile errors like:

1.c: In function âmainâ:
1.c:36: error: too few arguments to function âprintMenuâ

I just want to call the menu again when the switch goes to default. How can I do that?

[Salem]

> selection = printMenu(selection);
Here you call it with one argument.

> printMenu();
And here you don't.

Now exactly what part of "too few arguments" is confusing you?

[hk_mp5kpdw]

int printMenu(int menu)
{
   printf("1.)   Integer to Binary converter\n");
   printf("2.)   Fibonacci generator\n");
   printf("999.) Exit\n");
   printf("Enter selection ---> ");
   scanf("%d", &menu);

   return menu;
}

This function does not need to have an int argument passed in. Having one just so you can read a value into it and then return that value isn't the best use of a function argument. Ditch the argument and make the variable local:

int printMenu()
{
    int menu;
   printf("1.)   Integer to Binary converter\n");
   printf("2.)   Fibonacci generator\n");
   printf("999.) Exit\n");
   printf("Enter selection ---> ");
   scanf("%d", &menu);

   return menu;
}

Then just always call the function without an argument:

selection = printMenu();

[matsp]

And the above code [by original poster] still misses the while-loop to "go back and do it again" when the selection is wrong.

I'd prefer to see the "PrintMenu" function at the begging of some sort of loop, and not in the "Your selection is wrong" default statement. That way, the user can also select another choice after the first choice is finished [e.g. select 1 first time, then 2 for the second choice, and 999 to exit].

--
Mats