C Program to Find All Roots of a Quadratic Equation - Source Code, Output & Execution Flow

C Program to Find All Roots of a Quadratic Equation

This C program finds the roots of a quadratic equation using the discriminant.

#include <stdio.h>
#include <math.h>
int main() {
    double a, b, c, d, r1, r2;
    printf("Enter coefficients a, b and c: ");
    scanf("%lf %lf %lf", &a, &b, &c);
    d = b * b - 4 * a * c;
    if (d > 0) {
        r1 = (-b + sqrt(d)) / (2 * a);
        r2 = (-b - sqrt(d)) / (2 * a);
        printf("Roots are %.2lf and %.2lf
", r1, r2);
    } else if (d == 0) {
        r1 = -b / (2 * a);
        printf("Root is %.2lf
", r1);
    } else {
        printf("Roots are imaginary.
");
    }
    return 0;
}

Enter coefficients a, b and c: 1 -5 6
Roots are 3.00 and 2.00

Practice This Program

In this program, the input is read first when required, the core logic is applied step by step, and the final result is displayed using printf(). Follow the execution flow beside the code to understand how each statement contributes to the output.