Solving Quadratic Equation.

quadratic.c

#include <stdio.h>
#include <math.h>
#define FIN "quadratic.in"
#define FOUT "quadratic.out"

typedef struct Q {

        float a, 
              b,
              c; 
    
} E;

float computeDelta(float a, float b, float c) {

      return b*b - 4*a*c; 
}

void displayEq(float a, float b, float c) {

     printf("%3.3f*x^2 + %3.3f*x +  %3.3f = 0\n", a, b, c); 
}

int main() {

    E q;
    float D;
    int i, n;
    E arr[100];

    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);

    scanf("%d", &n);   
   
    //read every equation
    for(i = 1; i<= n; ++i) scanf("%f %f %f", &arr[i].a, &arr[i].b, &arr[i].c);
     
    //solve the equations
    for(i = 1; i<= n; ++i) {

       q.a = arr[i].a;
       q.b = arr[i].b;
       q.c = arr[i].c;

       D = computeDelta(q.a,q.b,q.c); 

       displayEq(q.a, q.b, q.c);

       if(D < 0) printf("%s\n", "Equation do not have real solutions.");

           else if(D == 0) printf("x1 = x2 = %3.3f\n", -q.b/2*q.a);

                else if(D > 0) {

                       float x1, x2;
                       x1 = (-q.b + sqrt(D))/(2*q.a);  
                       x2 = (-q.b - sqrt(D))/(2*q.a);
                       printf("x1 = %3.3f x2 =%3.3f\n", x1, x2);  
                } 
     }

    return(0);
}