C program to find the roots of a quadratic equation

In this article we will learn to implement a C program to find the roots of a quadratic equation. A C program is provided below for calculating the roots of a quadratic equation ax^2+bx+c=0

Program is a follows:

//C program to find the roots of a quadratic equation. Ex: ax^2+bx+c=0
#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
	int a, b, c;
	double disc, r1, r2, real, imag;
	printf("Enter values of a, b and c: ");
	scanf("%d%d%d",&a,&b,&c);
	disc=(b*b)-(4*a*c);
	if(disc<0)
	{
		printf("Roots are imaginary...");
		real = -b/(2.0*a);
		imag = sqrt(-disc)/(2.0*a);
		printf("\nRoot r1 is: %d + i %lf",real,imag);
		printf("\nRoot r2 is: %d - i %lf",real,imag);
	}
	else if(disc==0)
	{
		printf("Roots are real and equal...");
		r1=-b/(2.0*a);
		r2=r1;
		printf("\nRoot r1 is: %lf",r1);
		printf("\nRoot r2 is: %lf",r2);
	}
	else
	{
		printf("Roots are real and distinct...");
		r1=(-b+sqrt(disc))/(2.0*a);
		r2=(-b-sqrt(disc))/(2.0*a);
		printf("\nRoot r1 is: %lf",r1);
		printf("\nRoot r2 is: %lf",r2);
	}
	getch();
}

Input and output for the above program is as follows:

Enter values of a, b and c: 2 4 2
Roots are real and equal...
Root r1 is: -1.000000
Root r2 is: -1.000000

Suryateja Pericherla

Suryateja Pericherla, at present is a Research Scholar (full-time Ph.D.) in the Dept. of Computer Science & Systems Engineering at Andhra University, Visakhapatnam. Previously worked as an Associate Professor in the Dept. of CSE at Vishnu Institute of Technology, India.

He has 11+ years of teaching experience and is an individual researcher whose research interests are Cloud Computing, Internet of Things, Computer Security, Network Security and Blockchain.

He is a member of professional societies like IEEE, ACM, CSI and ISCA. He published several research papers which are indexed by SCIE, WoS, Scopus, Springer and others.