Thread: One last question for the day

Greetings,

I have written a simple menu program, and am trying to get my error checking to work. What I am having problems with is if I enter a letter rather then a number. If I enter a number that is not an option, everything works great, but if I enter a letter, like F of H I get in some loop, and can not get out. I did search the boards and found a few things, but nothing that seems to clear up my issue, unless I want to rewrite my code. Obviously if I am way off, and need to rewrite it I can, but I am hoping someone might have an idea how I can correct my issue without redoing the whole thing.

Here is my code:

// Menu Driven Program

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>


int getMenu (void);
void function1 (void);
void fnction2 (void);
void function3 (void);

int main (void)
{
int done = 0;
int choose;

while (!done)
{
choose = getMenu ();
if (choose == 4)
done = 1;
else
switch (choose)
{
case 1: functionq ();
break;
case 2: functions2 ();
break;
case 3: function3();
break;
}
printf("\n\n");
}
return 0;
}


// --------------------getMenu--------------------

int getMenu (void)
{

int choice;


do
{
printf("\t**************************************** \n");
printf("\t* Menu *\n");
printf("\t* *\n");
printf("\t* 1. Option 1 *\n");
printf("\t* 2. Option 2 *\n");
printf("\t* 3. Option 3 *\n");
printf("\t* 4. Exit Program *\n");
printf("\t* *\n");
printf("\t**************************************** \n\n");

printf("Please select a menu optionh (1-4) and press <retrun>: ");
scanf("%d", &choice);

if (choice <1 || choice >4)
printf("\aSorry, but this is not a valid option. Please select again.\n\n");

} while (choice <1 || choice >4);

return choice;

}

All ideas and help is appreciated.

Thanks,
DD

>scanf("%d", &choice);
should be something more like

Code:

if ( scanf("%d", &choice) != 1 ) {
  /* Inform the user */
  puts ( errMsg );
  /* Remove the culprit */
  while ( getchar() != '\n' );
  /*
  ** Further error handling goes here.
  */
}

-Prelude

If I replace the:

if (choice <1 || choice >4)
printf("\aSorry, but this is not a valid option. Please select again.\n\n");

with
if ( scanf("%d", &choice) != 1 ) {
puts ( errMsg );
while ( getchar() != '\n' );
}

I start to have problems with all my number options. I am not sure why this happens. If I select a valid option now, it does not accept my first entry, and I have to do it twice. (i.e. 2 2 to get option 2 to work. But it does resolve all my issues with loop I was getting when I entered an letter instead of number.

Any other thoughts?

Thanks,
DD

OK, finally got it. The line:

while ( getchar() != '\n' );
Was the magical option for me. I kept everything else the same, but added that line in, and it now handles my problem with the letters and numbers...See below:

scanf("%d", &choice);
if (choice <1 || choice >4)
{
printf("\aSorry, but this is not a valid option. Please select again.\n\n");
while ( getchar() != '\n' );
}
}
while (choice <1 || choice >4);

return choice;

Thanks again for the help. I apprecaite you getting me in the right course

DD

I am not sure what other problems you are getting, but here's an alternate version of you getMenu function.

Code:

int getMenu(void)
{
    int choice, rc;

    while (1)
    {
        printf("\t****************************************\n");
        printf("\t* Menu *\n");
        printf("\t* *\n");
        printf("\t* 1. Option 1 *\n");
        printf("\t* 2. Option 2 *\n");
        printf("\t* 3. Option 3 *\n");
        printf("\t* 4. Exit Program *\n");
        printf("\t* *\n");
        printf("\t****************************************\n\n");

        printf("Please select an option and press <enter>: ");
        rc = scanf("%d", &choice);
        while (getchar() != '\n');
        if (rc != 1 || choice < 1 || choice > 4)
            printf("\aSorry, but this is not a valid option. Please select again.\n\n");
        else break;        
    }

    return(choice);
}

See if this helps you or not.

[EDIT]Oopps, I see I'm slow posting this one, you've fixed it already!