Quadratic Equation not working properly - c

Question

I am new to both this site and C programming and I am attempting to make a quadratic formula but I cannot get the roots to work. I believe I am not calling a function or perhaps there is something else wrong. Any help would be appreciated, thank you!
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
float userinput(char prompt[]); //Function Prototype
float root(float a, float b, float c);
int main()
{
float a,b,c;
a=userinput("Enter the value for a:"); //Function Call
b=userinput("Enter the value for b:");
c=userinput("Enter the value for c:");
printf("The Equation you entered is |n%fx^2%+fx%+f=0", a, b, c);
return 0;
}
float root(float a, float b, float c)
{
float D,x,x1,x2,x3,x4;
D = b*b - 4*a*c;
if(D>0)
{
printf("There are two real roots, the roots are: ");
x1 = ((-b+(sqrt(D)))/(2*a));
x2 = ((-b-(sqrt(D)))/(2*a));
printf("%.2f and %.2f,x1 , x2");
}
if(D==0)
{
printf("There is one real root, the root is: ");
x = ((-b)/(2*a));
printf("%.2f,x");
}
if(D<0)
{
printf("There are two imaginary roots. The roots are: ");
x3 = ((-b/2*a)+(sqrt(fabs(D))/(2*a)));
printf("%.2f,x3i and");
x4 = ((-b/2*a)-(sqrt(fabs(D))/(2*a)));
printf("%.2f,x4i");
}
}
float userinput(char prompt[]) //Function definition
{
float answer;
int status;
do
{
printf("%s",prompt);
status=scanf("%f", &answer);
if(status!=1)
{
fflush(stdin);
printf("INPUT ERROR!\n");
}
}
while(status!=1);
return answer;
}

Answer 1

You never call the function root() so it will never be executed. Put the function call somewhere before return 0; of main():
root(a, b, c);
Also, fix the printf() calls as mentioned above.

Answer 2

I'm not sure if this will fix everything but in your code you have your print statements formatted incorrectly. For example, this line:
printf("%.2f and %.2f,x1 , x2");
Should be printf("%.2f and %.2f", x1, x2);
The variables whose values you are trying to use should be outside of the quotation marks. Hopefully this helps.

Answer 3

You have several errors.
You never call root().
root is declared to return float, but it doesn't return anything, it just prints the roots. It should be declared void.
You have mistakes in many of your printf() calls. When you're displaying the equation, you have |n instead of \n, and %+f instead of +%f. When you're displaying the roots, you have the variables that you want to print inside the format string, instead of as separate arguments to printf.
Here's the corrected code.
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
float userinput(char prompt[]); //Function Prototype
void root(float a, float b, float c);
int main()
{
float a,b,c;
a=userinput("Enter the value for a:"); //Function Call
b=userinput("Enter the value for b:");
c=userinput("Enter the value for c:");
printf("The Equation you entered is \n%fx^2+%fx+%f=0\n", a, b, c);
root(a, b, c);
return 0;
}
void root(float a, float b, float c)
{
float D,x,x1,x2,x3,x4;
D = b*b - 4*a*c;
if(D>0)
{
printf("There are two real roots, the roots are: ");
x1 = ((-b+(sqrt(D)))/(2*a));
x2 = ((-b-(sqrt(D)))/(2*a));
printf("%.2f and %.2f" ,x1 , x2);
}
if(D==0)
{
printf("There is one real root, the root is: ");
x = ((-b)/(2*a));
printf("%.2f",x);
}
if(D<0)
{
printf("There are two imaginary roots. The roots are: ");
x3 = ((-b/2*a)+(sqrt(fabs(D))/(2*a)));
printf("%.2fi and ", x3);
x4 = ((-b/2*a)-(sqrt(fabs(D))/(2*a)));
printf("%.2fi", x4);
}
}
float userinput(char prompt[]) //Function definition
{
float answer;
int status;
do
{
printf("%s",prompt);
status=scanf("%f", &answer);
if(status!=1)
{
fflush(stdin);
printf("INPUT ERROR!\n");
}
}
while(status!=1);
return answer;
}
DEMO