scanf and blank input.

[Mini]

I'm currently using scanf to read in numbers and then to use CTRL+D to signal to the program EOF... but how could I say put in numbers "2 34 23 22 19" and then when I press "ENTER", it automatically knows to stop scanning in numbers?

I need to somehow make this program stop if there is 'empty input' and spit out an error message...

Thanks

[Elysia]

The input should look like:
"2 34 23 22 19\n"
So read number. Read whitespace. Repeat until the whitespace is == '\n'.
That should get you started.

[Mini]

Yeah okay, but scanf doesn't read in white spaces unless if you use %c I think...

and that would be a pain too if I used %c instead of %d because it would also read in spaces...

Am I missing something?

[Elysia]

Who says you can't read a number first with %d and then a whitespace with %c? %c isn't a string, btw, it is a character. So it will read one and one character only. Not a string.

[Mini]

Okay,

atm I have this

   scanf("%c",&a);
   while(scanf("%d", &num[i])!=EOF && a!='\n') {
      n++;
      i++;
   }

the idea being that if I just press "ENTER" it will show an error that no input was entered...

However, the problem with this is that it removes the first number if I enter numbers seperated with spaces.

What would be a better approach to this?

Thanks

[Elysia]

How about...

int num;
do
{
    if (scanf("%d", &num) == 1)
    {
        // Read succeeded; do your logic.
    }
}
while (getchar() != '\n');

[Mini]

Thanks for that... it is ingenious... but it still doesn't work if I just press "enter" without typing anything

Would you have an alternative method now?

[Elysia]

Annoying sscanf. Won't advance the buffer. Hah.
This had to call for some more advanced parsing:

// Test.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>

int main()
{
    long num;
    char c;
    char buf[1024];
    char * pEnd;
    char * pStart = buf;
    fgets(buf, sizeof(buf), stdin);

    do
    {
        num = strtol(pStart, &pEnd, 10);
        if (pStart != pEnd)
        {
            // Read succeeded; do your logic.
            printf("YAY!");
        }
        pStart = pEnd;
        c = *pStart++;
    }
    while (c != '\n');
}

[Bayint Naung]

>>I need to somehow make this program stop if there is 'empty input' and spit out an error message...
Then you would need something else.
Do you want 12 23 10 as valid input or just one number per line?
And you should read scanf man.