Where is the Third variable stored?

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C#

int _tmain(int argc, _TCHAR* argv[])
{
    int a;
    float b;
   
    scanf("\n%d %f ",&a,&b);
    printf("\n%d %f",a,b);
    return 0;
}

In the above program , Because of space given after %f scanf will wait for third value before printing a and b . My doubt is where will the third value stored? Will space be allocated for it

Posted 29-Oct-12 22:14pm

steven8Gerrard

Updated 29-Oct-12 22:17pm

Mohibur Rashid

v2

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CPallini 30-Oct-12 5:21am

Note, always check scanf return value, namely:
if ( scanf("%d %f", &a, &b) != 2 )
{
// handle error
}

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OriginalGriff · Answer 1 · 2012-10-29T22:26:00

Solution 1

What third variable? What third value?
When you call scanf it allocates space for the user input on the stack, reads from the keyboard up to an ENTER, then processes the input string according to the format you provide. There is no third variable involved, as you only supply two addresses and a constant format string.

Posted 29-Oct-12 22:26pm

OriginalGriff

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steven8Gerrard 30-Oct-12 7:25am

Since space is given after "%f" . Cursor wait till third value is typed before printing a & b . Check it

Chuck O'Toole · Answer 2 · 2012-10-30T05:17:00

"Spaces" in the format string for scanf, an input function, are there to direct the scan to "discard" characters in the scanned string. So your format calls for a number (%d), discard a space (the space in the format string), another number (%f), discard another space, then no more format specifiers.

Scanf is not waiting for you to type another number, it's waiting for you to type another space.

Since you did not provide any additional variables (beyone a and b), anything you typed after that last space is ignored, discarded, thrown into the plasma pool, evaporated into the ether. No storage is allocated and it doesn't go anywhere (like Ocean Breeze Soap - extra credit if you know the movie reference) :)