X

C Program to Find the Roots of a Quadratic Equation

In this example, you will learn to find the roots of a quadratic equation in C programming.

Limited time offer: Get 10 free Adobe Stock images.ADS VIA CARBON

To understand this example, you should have the knowledge of the following C programming topics:


The standard form of a quadratic equation is:

ax2 + bx + c = 0, where
a, b and c are real numbers and
a != 0

The term b2-4ac is known as the discriminant of a quadratic equation. It tells the nature of the roots.

  • If the discriminant is greater than 0, the roots are real and different.
  • If the discriminant is equal to 0, the roots are real and equal.
  • If the discriminant is less than 0, the roots are complex and different.
Figure: Roots of a Quadratic Equation

Program to Find Roots of a Quadratic Equation

#include #include int main() { double a, b, c, discriminant, root1, root2, realPart, imagPart; printf("Enter coefficients a, b and c: "); scanf("%lf %lf %lf", &a, &b, &c); discriminant = b * b - 4 * a * c; // condition for real and different roots if (discriminant > 0) { root1 = (-b + sqrt(discriminant)) / (2 * a); root2 = (-b - sqrt(discriminant)) / (2 * a); printf("root1 = %.2lf and root2 = %.2lf", root1, root2); } // condition for real and equal roots else if (discriminant == 0) { root1 = root2 = -b / (2 * a); printf("root1 = root2 = %.2lf;", root1); } // if roots are not real else { realPart = -b / (2 * a); imagPart = sqrt(-discriminant) / (2 * a); printf("root1 = %.2lf+%.2lfi and root2 = %.2f-%.2fi", realPart, imagPart, realPart, imagPart); } return 0; }

Output

Enter coefficients a, b and c: 2.3
4
5.6
root1 = -0.87+1.30i and root2 = -0.87-1.30i

In this program, the sqrt() library function is used to find the square root of a number. To learn more, visit: sqrt() function.

Categories: Uncategorized
ilexjjtt-ca: