Thread: Im getting a headache

lately I have been asking questions a bit over my head so Im trying to break things down a little so I can understand it better.

What Im trying to do is look at all integers and if any of them are not 0-9 then return an error.

I was doing well with this earlier today but I have looked at so many different ways to code this that Im starting to confuse myself. I was curious if someone could please look at what I have and see where my mistake is?
Thank you

Code:

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

int valid(); 

int main (void)
{
	int a;
	char buff[BUFSIZ];
	
	printf("Enter number: ");
	fgets(buff, BUFSIZ, stdin);
	sscanf("%d", &a);

	if( valid(buff, BUFSIZ, a))
		printf("Output: %d\n", a);
	else
		printf("This is an error string\n");
	
	getch();
}


int valid(int array[], int count, int a)
{	
	int i;

	for (i = 0; i < count; i++)
	{
		if (array[a] >= 0 && array[a] <= 9)
			return 1;
	}
return 0;
}

Like so

Code:

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

int valid(char array[], int count );

int main (void)
{
    int a;
    char buff[BUFSIZ];
    
    printf("Enter number: ");
    fgets(buff, BUFSIZ, stdin);

    if( valid(buff, strlen(buff)) ) {
        sscanf( buff, "%d", &a );
        printf("Output: %d\n", a);
    } else {
        printf("This is an error string\n");
    }
    return 0;
}

int valid(char array[], int count )
{   
    int i;

    for (i = 0; i < count; i++)
    {
        if ( array[i] == '\n' ) continue;   // ignore newline
        if (array[i] < '0' || array[i] > '9' )
            return 0;   // outside range
    }
    return 1;
}

You could also use the macros defined in ctype.h, like isdigit().

ok very nice, Im much closer.... but if a the input was something like : 54k6 it would accept 54 and not return an error?

What did I miss? I thought this would go through each character and if anything was not {0,1,2,3,4,5,6,7,8,9} then it would return an error?

Look at Salem's code. It works. The reason why your code doesn't catch it is because you only check one character and then return in your for loop. Also, I dunno why you used array[a], it should be array[i] like in Salem's code.

well Im home now and I was using salems code at work, but I swear it wasnt working properly.. but now that Im trying it from home.... I see it does work. go figure!

Well I guess that means tomorrow morning Im going to go back and check my connections. (ie.. make sure my head isnt connected to my ass!)

and why was I using a? Cause Im a newbie and dont know ____

=)

Thanks again