reading and writing into a file

[amateur073532]

Could somebody help me please!! I've tried to solve the problem but can't get it right.Here is the question:
Solve a quadratic equation using the coefficients in a file "coef.txt" .The file is as follows:
a b c
2 6 1
3 3 0
1 3 1
0 12 -3
3 6 3
2 -4 3
1) The coefficients are to be read in the main function
2) Get the the desired solutions in a function named quad(use the formula (- b + (sqrt(b*b-4*a*c)))/(2*a);)
3) The program should also be able to find complex numbers
real part=-b/2a
imaginary part=sqrt(4*a*c-b*b) i

3) Pass the coefficient and the the values of X1 and X2 in another function named calculated_quad
4) In that same function also,write the values in a file named "results.txt"

Here is what I've tried :

#include<stdio.h>
#include<math.h>
 
double quad(int a,int b,int c);
double quad2(int a,int b,int c);
void calculated_quad(double X1,double X2,int a,int b,int c);
 void main()
 {
  int a,b,c,i;
  double X1,X2;
  char A,B,C;
  FILE*val;
  val=fopen("coef.txt","r");
  fscanf(val,"%s%s%s",&A,&B,&C);
  for(i=0;i<6;i++)
  {
   fscanf(val,"%d%d%d",&a,&b,&c);
 
   X1=quad(a,b,c);
   X2=quad2(a,b,c);
   calculated_quad(X1,X2,a,b,c);
 
  }
  return;
 }
 
 
 
 
 double quad(int a,int b,int c)
 {
   double x;
   x=(-b + (sqrt(b*b-4*a*c)))/(2*a);
 
   return x;
 }
  double quad2(int a,int b,int c)
  {
   double x2;
   x2=(-b - (sqrt(b*b-4*a*c)))/(2*a);
 
   return x2;
  }
 
  void calculated_quad(double X1,double X2,int a,int b,int c)
  {
   double real,im,check;
   FILE*out;
   out=fopen("results.txt","w");
   fprintf(out," a   b   c      X1      X2\n");
   fprintf(out," -   -   -      --      --\n\n");
   check=b*b - 4*a*c;
   real=-b/(2*a);
   im=sqrt(4*a*c-b*b);
 
 
   if(check<0)
 
   fprintf(out,"%2d%4d%4d%9.2lf+%.2lfi%9.2lf-%.2lfi\n",a,b,c,real,im,real,im);
 
   else
 
   fprintf(out,"%2d%4d%4d%9.2lf%9.2lf\n",a,b,c,X1,X2);
 
   return;
  }

[donbock]

What's the problem?
> compiler error
> linker error
> run-time error
> wrong answer
> something else

Please describe the gap between what you expect and what you're getting.

[newb16]

@amateur073532
How are you handling non-quadratic, linear equations?
And why are all coefficients integer?
Btw, why did you decided to use "%9.2lf" for output?

[weaknessforcats]

What if the surd is negative resulting in complex roots?

[amateur073532]

never mine guys i've got the answers.Thanx a million...

#include<stdio.h>
#include<math.h>
 
 
void quad(int a,int b,int c,int i);
void calculated_quad(int a,int b,int c,double X1,double X2);
 
 void main()
 {
     int a,b,c,i;
     char A,B,C;
     FILE*coef_val;
     coef_val=fopen("coef.txt","r");
     fscanf(coef_val,"%s%s%s",&A,&B,&C);
     printf("---------------------------------------------------------------------\n");
     printf("    This program finds the solution for quadratic equation only!!\n\n");
     printf("---------------------------------------------------------------------\n");
 
     for(i=1;i<=6;i++)
     {
         fscanf(coef_val,"%d%d%d",&a,&b,&c);
         printf("Equation%d : %d(x2) + (%d)x + (%d)\n\n",i,a,b,c);
         quad(a,b,c,i);
 
     }
     printf("All the solutions for the equations have been written to the file results.txt   Feel free to view them!\n");
     return;
 }
 
 
 
 
 
 
void quad(int a,int b,int c,int i)
{
     double x1,x2;
     double real,im,check;
     FILE*out;
     out=fopen("results.txt","a");
     check=b*b - 4*a*c;
     if(i==1)
     {
         fprintf(out," a   b   c            X1            X2\n");
         fprintf(out," -------------------------------------------\n");
     }
 
 
     if(a==0)
     {
 
         fprintf(out,"%2d%4d%4d         undefined      undefined (#This is not a quadratic equation)\n",a,b,c);
     }
     else if(check<0)
     {
         real=(-b)/(2*a);
         im=(sqrt(4*a*c-b*b))/(2*a);
         calculated_quad(a,b,c,real,im);
     }
 
     else
     {
         x1=(-b + (sqrt(b*b-4*a*c)))/(2*a);
         x2=(-b - (sqrt(b*b-4*a*c)))/(2*a);
         calculated_quad(a,b,c,x1,x2);
     }
 
    return;
}
 
 
 
 
 
void calculated_quad(int a,int b,int c,double X1,double X2)
{
    double check;
    FILE*out;
    out=fopen("results.txt","a");
 
    check=b*b - 4*a*c;
 
 
    if(check<0)
 
        fprintf(out,"%2d%4d%4d%12.2lf+%.2lfi%10.2lf-%.2lfi\n",a,b,c,X1,X2,X1,X2);
 
    else
 
        fprintf(out,"%2d%4d%4d%15.2lf%15.2lf\n",a,b,c,X1,X2);
 
     return;
 
}