Question

I wrote this code:

 char str[10];

    while(1)
    {
       scanf("%d",str);  
    }

if given a char (‘a’ for example) the loop just keep on going without stopping and asking for more input (the scanf isn’t blocking suddenly)

why is that? 🙂

Answer 1

Because a is not a decimal integer. scanf will attempt to read it but fail and not advance it’s internal pointer, thus it will endlessly try to read the same a as a decimal and fail.

consider the following program:

int d;
char c;
scanf("%d", &d);
scanf("%c", &c);

if you enter a the first scanf will fail and the second will read ‘a‘ into c. This should explain the problem 🙂