multiple character input to char in C

Question

#include <stdio.h>

int main(void) {
   char ch,ch1;
   scanf("%c",&ch);/*input ab here*/
   scanf("%c",&ch1);
   printf("%c %c",ch,ch1);
   return 0;
}

Why this produces a b as output. We don't enter any input for second variable but it still got assigned. Could anyone explain the behavior.

You can check the output here if you want.

Answer 1

We don't enter any input for second variable

That's not true, "%c" in scanf reads one character, after it processes the input a, the "%c" in the next scanf then reads the next input character b.

Answer 2

Because you entered 2 characters in the 1st input while the program expects just 1: the 2nd is pending until the next call to scanf

Answer 3

this may get you rid of the situation

scanf("%c",&ch);/*input ab here*/
fflush(stdin);
scanf("%c",&ch1);

EDIT Your actual problem is that ch1 is being assigned with the newline character(or the space as tried in IDEONE simulator)

To check that : enter your values without any separation.

Answer 4

Scanf can do multiple scans:

char a1, a2, a3, a4;
scanf("%c%c%c%c", &a1, &a2, &a3, &a4);