Fungsi (C)

#include"stdio.h"
#include"conio.h"

double hitung(double total);
void main(){
    double Harga,disc=0;
    printf("Total Harga:");
    scanf("%lf",&Harga);
    printf("Discount:%.0lf",hitung(Harga));
}
double hitung(double total){
    double discount;
    if(total>=2000000)
        discount=0.1*total;
    else if(total>=1000000)
            discount=0.5*total;
    else
        discount=0;
    return(discount);
}