Input of double is improper eventhoug converter is - c

Question

I've been struggling with the following program that helps me cheat in my maths class calculating the quadratic equation:
/*Improved version of my maths cheat code -w-,
this program has the same functionality as the last but with
cleaner and more correct code. Notes taken from the post made in
codereview.stackechange to make it less of a dumpster fire.
The program is not functional already.*/
#include<stdio.h>
#include<math.h>
double a,b,c,d;
//Get values of the equation
void get_values (void){
printf("Dame el valor de a: ");
scanf("%g", &a);
printf("Dame el valor de b: ");
scanf("%g", &b);
printf("Dame el valor de c: ");
scanf("%g", &c);
}
//Calculates the discriminante
double discriminante (double a, double b, double c){
double result;
result = b*b-4*a*c;
return result;
}
//Prints the result of the equation based on the square root
//of the discriminate
void display (double d){
if (d>0){
printf("El resultado es: (%g±%g)/%g\n", -b, sqrt(d), a*2);
}
else if (d<0){
printf("El resultado es: (%g±%gi)/%g\n", -b, sqrt(-d), a*2);
}
else { // d == 0
printf("El resultado es: %g/%g\n", b, a*2);
}
}
int main(){
get_values();
d = discriminante(a,b,c);
printf("El valor del discriminante es: %g\n",d);
display(d);
return 0;
}
I made a post in codereview.stackexchange to get some feedback on my code. After rewritting the thing in a cleaner generally better way, I found the small issue that the functions never take the input properly. I've checked the scanf and converters for an hour now, and I'm just baffled at this point on why it just refuses to take input properly. Did I use an improper converter or did I made an error at discriminante?

Answer 1

%g in scanf() is for reading float. You should use %lg to read double.
Note that using %g in printf() to print double is fine.