Write a C Program to find all Roots of a Quadratic Equation

 

Question:

Write a C Program to find all Roots of a Quadratic Equation

Answer:

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.

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C Language programming code to find root of quadratic equation:

/* C program to find roots of a quadratic equation */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
 
// Prints roots of quadratic equation ax*2 + bx + x
void findRoots(double a, double b, double c)
{
	double sqrt_val;
    // If a is 0, then equation is not quadratic, but
    // linear
    if (a == 0) {
        printf("Invalid");
        return;
    }
 
    int d = b * b - 4 * a * c;
    sqrt_val = sqrt(abs(d));
 //If the discriminant is greater than 0, the roots are real and different.
    if (d > 0) {
        printf("Roots are real and different \n");
        printf("%f\n%f", (-b + sqrt_val) / (2 * a),
               (-b - sqrt_val) / (2 * a));
    }
    //If the discriminant is equal to 0, the roots are real and equal.
    else if (d == 0) {
        printf("Roots are real and same \n");
        printf("%f", -b / (2 * a));
    }
    //If the discriminant is less than 0, the roots are complex and different.
    else // d < 0
    {
        printf("Roots are complex \n");
        printf("%f + i%f\n%f - i%f", -b / (2 * a),
               sqrt_val, -b / (2 * a), sqrt_val);
    }
}
 
// Driver code
int main()
{
    double a ,b,c;
    printf("Enter a, b and c where a*x*x + b*x + c = 0\n");
    printf("Enter coefficients a, b and c: ");
    scanf("%lf %lf %lf", &a, &b, &c);

    
   
    // Function call
    findRoots(a, b, c);
    return 0;
}

 

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SCREENSHOOT OF RUNNING PROGRAM:

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SCREENSHOOT OF OUTPUT WINDOW: