can't do multiplication operation on 'double' numbers

Question

I am trying to write some functions for Complex type numbers, but I couldn't make this work.

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

typedef struct{
double a; /* Real*/
double b; /* Imaginary*/
}Complex;
Complex Nmbr1,Nmbr2;

int main()
{
Complex NmbrMulti;
printf("Type the value of the real part of the first number\n");
scanf("%d",&Nmbr1.a);
printf("\nType the value of the Imaginary part of the first number\n");
scanf("%d",&Nmbr1.b);
printf("\nType the value of the real part of the second number\n");
scanf("%d",&Nmbr2.a);
printf("\nType the value of the Imaginary part of the second number\n");
scanf("%d",&Nmbr2.b);

   NmbrMulti.a = Nmbr1.a  * Nmbr2.a  - Nmbr1.b * Nmbr2.b ;
   NmbrMulti.b = Nmbr1.a * Nmbr2.b + Nmbr2.a * Nmbr1.b ;

  printf("\nThe Multiplication : %d+i", NmbrMulti.a);
  printf("%d\n", NmbrMulti.b);

return 0;
}

but I get the result 0+i0 , it seems that the problem is with the operations, is there another way to do multiplication for double numbers that I'm not aware of ?

Answer 1

When scanf sees %d, the corresponding argument must be a pointer to int. If the argument is a pointer to double, the code should be %lf.

Reference
http://www.cplusplus.com/reference/cstdio/scanf/

Answer 2

Formatting for double in C is lf rather than d. The latter implies and int.