Question

In the below program when am reading input from keyboard its taking only 2 characters instead of 4 and remaining 2 characters its taking spaces by default.
why is it???

program to take char input through pointers/

int c,inc,arrysize;
char *revstring;
printf("enter the size of char arry:");
scanf("%d",&arrysize);
revstring = (char *)malloc(arrysize * sizeof(*revstring));
printf("%d",sizeof(revstring));
printf("enter the array elements:");
for(inc=0;inc<arrysize;inc++)
{
scanf("%c",&revstring[inc]);

}
for(inc =0;inc<arrysize;inc++)
    printf("%c",revstring[inc]);
getch();
return 0;

}

Answer 1

scanf reads formatted inputs. When you tape a number, you tape the digits, and then, you press <Enter>. So there is a remaining \n in stdin, which is read in the next scanf. The same applies if you press <Enter> between the characters.

A solution is to consume the characters in the standard input stream after each input, as follow:

#include <stdio.h>

void
clean_stdin (void)
{
  int c;

  while ((c = getchar ()) != '\n' && c != EOF)
    ;
}

Another idea is to use fgets to get human inputs. scanf is not suitable for such readings.