C Program to Solve Quadratic Equations along with Types of Root

Program

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

void main()
{
	 float a, b, c, d, r1, r2, rp, ip;
	 clrscr();
	 printf("Enter coefficients a, b and c: \n");
	 scanf("%f%f%f", &a, &b, &c);
	 
	 d = b*b - 4*a*c;
	 
	 if( d == 0)
	 {
	  r1 = -b / (2*a);
	  r2 = r1;
	  printf("Roots are real and equal.\n");
	  printf("Root1 = %f\n", r1);
	
	  printf("Root2 = %f", r2);
	 }
	 else if(d > 0)
	 {
	  r1 = (-b + sqrt(d))/ (2*a);
	  r2 = ( -b - sqrt(d))/(2*a);
	  printf("Roots are real and unequal.\n");
	  printf("Root1 = %f\n", r1);
	  printf("Root2 = %f", r2);
	
	 }
	else
	{
	  rp = -b/(2*a);
	  ip = sqrt(-d)/(2*a);
	  printf("Roots are Imaginary.\n");
	  printf("Root1 = %f + %f i\n", rp, ip);
	  printf("Root2 = %f - %f i", rp, ip);
	}
	getch();
}

Output of the above program :

Run 1:
-----------------
Enter coefficients a, b and c:
1 ↲
-4 ↲
4 ↲
Roots are real and equal.
Root1 = 2.000000
Root2 = 2.000000

Run 2:
-----------------
Enter coefficients a, b and c:
1 ↲
-5 ↲
6 ↲
Roots are real and unequal.
Root1 = 3.000000
Root2 = 2.000000

Run 3:
-----------------
Enter coefficients a, b and c:
1 ↲
2 ↲
3 ↲
Roots are imaginary.
Root1 = -1 + 1.414214 i
Root2 = -1 – 1.414214 i 

Note: ↲ indicates enter is pressed.