Thread: validation

Hi, can someone tell me what's wrong with this code?

Code:

        while ((num <= 1) && (num >= 9999)) {
        printf("\n");
        printf("\tinventory number: ");
        scanf("%d", &num);
        if (num <= 1)
        printf("Invalid entry\n");
        printf("Please enter a value greater than or equal to 1\n");
        if (num >= 9999)
        printf("Invalid entry\n");
        printf("Please enter a value less than or equal to 9999");
        }

I want it to ask for an inventory number until the user enters a number between 1-9999 and give an error message if the number is outside of that range.

can someone tell me what's wrong with this code?

The most glaring thing is the lack of indentation
Second is that you need a OR and not an AND
Third instead of having two if statements change it to one

Code:

while ( (num <= 1) || (num >= 9999) )
{
  printf("\n");
  printf("\tinventory number: ");
  scanf("%d", &num);
  if (num <= 1 || num >= 9999)
  {
    printf("Invalid entry\n");
    printf("Please enter a value between 1 and 9999\n");
  }
}

Code:

        while ((num <= 1) && (num >= 9999)) {
        printf("\n");
        printf("\tinventory number: ");
        scanf("%d", &num);
        if (num <= 1)
        printf("Invalid entry\n");
        printf("Please enter a value greater than or equal to 1\n");
        if (num >= 9999)
        printf("Invalid entry\n");
        printf("Please enter a value less than or equal to 9999");
        }

The evaluation in your while loops wants number less then 1 or a number greater then 9999, but your second if statement will givea validation error if the user selected number is in fact greater than 9999. Isn't this contradicting?

I think you want:

Code:

while (num >= 1 && num <= 9999) {

Hammer, can you briefly explain what your code is doing here?

Code:

int main(void)
{
  validate('F', 'Z');
  validate('N', 'M');
  validate('Z', 'Z');
  return(0);
}

Here's how I'm trying to implement it:

Code:

while (valid != 1)
                {
                        printf("\tcategory\t: ");
                        while (getchar() != '\n');
                                scanf("%c%c", &cat1, &cat2);

                        void validate(int ch1, int ch2)
                        {
                                switch (ch1)
                                {
                                        case 'F':
                                        if (strchr("DMNPS", ch2))
                                {
                                        valid = 1;
                                }
                                else
                                {
                                        puts("Second character must be D,M,N,P,or S");
                                }
                                        break;

                                case 'N':
                                if (strchr("AHMPS", ch2))
                                {
                                        valid = 1;
                                }
                                else
                                {
                                        puts("Second character must be A,H,M,P,or S");
                                }
                                        break;

                                default:
                                        puts("First character must be F or N");

                                        break;
                        }

                        validate(ch1, ch2);
                }

Posted by OOPboredom
I think you want:

Code:

while (num >= 1 && num <= 9999) {

If you re-read the error messages inside the loop you will see that he wants numbers in the range from 1 to 9999 inclusive. Or you can just re-read his first post[qoute]I want it to ask for an inventory number until the user enters a number between 1-9999[/quote]
Now I can make one little change to your loop to make it valid though

Code:

while ( !(num >= 1 && num <= 9999) ) {