scanf() skip variable

In C, using scanf() with the parameters, scanf("%d %*d", &a, &b) acts differently. It enters value for just one variable not two!

Please explain this!

scanf("%d %*d", &a, &开发者_开发知识库b);

The * basically means the specifier is ignored (integer is read, but not assigned).

Quotation from man scanf:

 *        Suppresses assignment.  The conversion that follows occurs as
          usual, but no pointer is used; the result of the conversion is
          simply discarded.

Asterisk (*) means that the value for format will be read but won't be written into variable. scanf doesn't expect variable pointer in its parameter list for this value. You should write:

scanf("%d %*d",&a);

http://en.wikipedia.org/wiki/Scanf#Format_string_specifications

An optional asterisk (*) right after the percent symbol denotes that the datum read by this format specifier is not to be stored in a variable.

The key here is to clear the buffer, so scanf will not think that it already has some input, and so it will not get skipped!

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

void main() {
    char operator;
    double n1, n2;

    printf("Enter two operands: ");
    scanf("%lf %lf",&n1, &n2);
    
   fflush(stdin);   //do this between two scanf
    
    printf("Enter an operator (+, -, *, /): ");
    scanf("%c", &operator);

}

fflush(stdin); //this clears the scanf for new input so it does not ignore any input taking line becuase it has some charater already stored in its memory