Thread: Figured Out the Quadratic Equation Solver, Looking to Optimize

  1. #1
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    Figured Out the Quadratic Equation Solver, Looking to Optimize

    I recently posted a thread that had a few things going on with a program I was working on, the code in question was full of useless code and other such issues that I hadn't managed to fully clean out before posting it to look for help with my questions, but I was able to basically figure out how to get everything to work how I was wanting it to.

    I recently posted a thread that had a few things going on with a program I was working on, the code in question was full of useless code and other such issues that I hadn't managed to fully clean out before posting it to look for help with my questions, but I was able to basically figure out how to get everything to work how I was wanting it to.

    The old code that I had posted was something along the lines of:

    Code:
    #include <stdio.h>
    
    #include <math.h> //void single_quad(); void wrong_choice(); void no_letters_a(); void no_letters_b(); void no_letters_c(); void input_a(); void input_b(); void input_c(); void run_calc(); int main(double a, double b, double c)//this bit here was already pointed out, it was part of my attempts to figure out pointers, hadn't cleared it out before posting the old code { double a; double b; double c; char choice = ' '; do { input_a(); getc(stdin); printf("\nIf you would like to input another equation, please hit 'y', otherwise hit 'n':\t"); scanf_s("%c", &choice, 1); if (choice == '%c') { do { wrong_choice(); getc(stdin); } while (choice != 'y', choice != 'n');//here goes the function for when a character other than 'y' or 'n' is input } printf("\n"); }while (choice == 'y'); return 0; } void input_a() { double a; printf("Please enter the variable for 'a':\t"); scanf_s("%lf", &a); if (a == '%lf') { do { no_letters_b(); getc(stdin); } while (a > 2000000000 || a < -2000000000); } input_b(); return a; //printf("%lf\n", a); } void input_b() { double b; printf("Please enter the variable for 'b':\t"); scanf_s("%lf", &b); if (b == '%lf') { do { no_letters_b(); }while (b > 2000000000 || b < -2000000000); } input_c(); return b; } void input_c() { double c; printf("Please enter the variable for 'c':\t"); scanf_s("%lf", &c); if (c == '%lf') { do { no_letters_c(); }while (c > 2000000000 || c < -2000000000); } run_calc();// it's here I keep running into an issue, "too few arguments in function to call" is all I get return c; } void run_calc(double a, double b, double c) { double a_calc = a; double b_calc = b; double c_calc = c; printf("\na = %lf\nb = %lf\nc = %lf\n", &a_calc, &b_calc, &c_calc); double d = -a_calc; double e = -b_calc; double f = -c_calc; | | | |//all these lines are where the equation's code is, took up well over half the post with that alone so I cut it out | | } void wrong_choice() { char choice = ' '; printf("I'm sorry, that selection is not recognized, please input 'y' for yes or 'n' for no."); scanf_s("%c", &choice, 1); printf("\n"); } void no_letters_a() { double a; getc(stdin); printf("\nI'm sorry, you have input an unrecognized value, please input a numeric digit:\t"); scanf_s("%lf", &a); if (a < 2000000000 && a > -2000000000) { input_b(); } else { no_letters_a(); } } void no_letters_b() { double b; printf("\nI'm sorry, you have input an unrecognized value, please input a numeric digit:\t"); scanf_s("%lf", &b); if (b < 2000000000 && b > -2000000000) { input_c(); } else { no_letters_b(); } } void no_letters_c() { double a; double b; double c; printf("\nI'm sorry, you have input an unrecognized value, please input a numeric digit:\t"); scanf_s("%lf", &c); if (c < 2000000000 && c > -2000000000) { run_calc(); } else { no_letters_c(); }
    }


    The new code is below, this time I left in the part that actually runs through the equation, as I'm looking for any tips, tricks, advice, etc for ways I could maybe optimize things... Basically looking to see if there are any ways of doing things easier than I have, and if there are, what those ways would be. Only have like 3 weeks experience doing anything with programming language at all, so trying to build my skills with it as soon as I can, I appreciate any help that might be offered.

    Code:
    #include <stdio.h>
    #include <math.h>
    
    void wrong_choice(char* choice);
    void wrong_a(double* a);
    void wrong_b(double* b);
    void wrong_c(double* c);
    void input_a(double* a);
    void input_b(double* b);
    void input_c(double* c);
    void run_calc(double* a, double* b, double* c);
    int main(void)
    {
     double a;
     double b;
     double c;
     char choice = ' ';
     
     do
     {
      input_a(&a);
      input_b(&b);
      input_c(&c);
    
      printf("\na = %lf\nb = %lf\nc = %lf\n", a, b, c);
    
      run_calc(&a, &b, &c);
      getc(stdin);
      printf("\nIf you would like to input another equation, please hit 'y', otherwise hit 'n':\t");
      scanf_s("%c", &choice, 1);
      if (choice != 'y' && choice != 'n')
      {
       wrong_choice(&choice);
      }
      printf("\n");
     }while (choice == 'y');
     
     return 0;
    }
    void input_a(double* a)
    {
     printf("Please enter the variable for 'a':\t");
     scanf_s("%lf", a);
     if (*a > 2000000000 || *a < -2000000000)
     {
      wrong_a(a);
     }
    }
    void input_b(double* b)
    {
     printf("Please enter the variable for 'b':\t");
     scanf_s("%lf", b);
     
     if (*b > 2000000000 || *b < -2000000000)
     {
      wrong_b(b);
     }
    }
    void input_c(double* c)
    {
     printf("Please enter the variable for 'c':\t");
     scanf_s("%lf", c);
     if (*c > 2000000000 || *c < -2000000000)
     {
      wrong_c(c);
     }
    }
    void run_calc(double* a, double* b, double* c)
    {
     double d = -(*a);
     double e = -(*b);
     double f = -(*c);
     if (a > 0 && b > 0 && c > 0)//if statements set up quadratics for different uses of +/- signs, needs to be reviewed to make sure all combinations are used
     {
      printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx+%.0lf.\n", a, b, c);
     }
     else
      if (a > 0 && b > 0 && c < 0)
      {
       printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx-%.0lf.\n", a, b, f);
      }
      else
       if (a > 0 && b < 0 && c > 0)
       {
        printf("\nThe quadratic equation entered is: %.0lfx^2-%.0lfx+%.0lf.\n", a, e, c);
       }
       else
        if (a < 0 && b > 0 && c > 0)
        {
         printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx+%.0lf.\n", a, b, c);
        }
        else
         if (a < 0 && b < 0 && c < 0)
         {
          printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx+%.0lf.\n", a, e, f);
         }
         else
          if (a > 0 && b < 0 && c < 0)
          {
           printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx+%.0lf.\n", a, e, f);
          }
          else
           if (a > 0 && b > 0 && c < 0)
           {
            printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx+%.0lf.\n", a, b, f);
           }
           else
            if (a < 0 && b > 0 && c < 0)
            {
             printf("\nThe quadratic equation entered is: %.0lfx^2+%.0lfx+%.0lf.\n", a, b, f);
            }
    
     double f1 = -(*b);
     double f2 = ((*b) * (*b)) - (4 * (*a) * (*c));
     double f3 = sqrt(f2);
     double f3_5 = sqrt(-f2);
     double f4 = 2 * (*a);
     double f5 = (f1 + f3) / f4;
     double f6 = (f1 - f3) / f4;
     double f7 = -(*c) / (*b);
     double f8 = sqrt((-f2 / f3_5));
     double f9 = -sqrt((-f2 / f3_5));
     if (a == 0 && b == 0)
     {
      printf("\nERROR.  Input not allowed. Variables 'a' and 'b' cannot both be 0.\n\n");
     }
     else if (a == 0)
     {
      printf("\nThe equation given is in the linear format.  The answer is x=%lf.\n", f7);
     }
     else if (f2 < 0)
     {
      printf("\nThe discriminate of the equation given equals %lf.\nTherefore, this is a complex number.\n", f2);
      if (f8 == f9)
      {
       printf("\nThe x-intercept is the complex number %lf+%lfi.\nThe solutions is %lf+%lfi.\n", f1 / f4, f8, f1 / f4, f8);
      }
      else if (f8 != f9)
      {
       printf("\nThe x-intercepts are the complex numbers %lf+%lfi and %lf-%lfi.\nThe solutions are x=%lf+%lfi or x=%lf-%lfi.\n", f1 / f4, f8, f1 / f4, f8, f1 / f4, f8, f1 / f4, f8);
      }
     }
     else
     {
      printf("\nThe discriminate of the equation given equals %lf.\nTherefore, this is not a complex number.\n", f2);
      if (f5 == f6)
      {
       printf("\nThere is only one x-intercept: (%.0lf,0).\nThe solution is x=%lf", f5, f5);
      }
      else
      {
       printf("\nThe x-intercepts are: (%.0lf,0), and (%.0lf,0).\nThe solutions are x=%lf or x=%lf.\n", f5, f6, f5, f6);
      }
     }
    }
    void wrong_choice(char* choice)
    {
     getc(stdin);
     printf("I'm sorry, that selection is not recognized, please input 'y' for yes or 'n' for no:\t");
     scanf_s("%c", choice, 1);
     if (*choice != 'y' && *choice != 'n')
     {
      do
      {
       wrong_choice(choice);
      } while (*choice != 'y' && *choice != 'n');
     }
     printf("\n");
    }
    void wrong_a(double* a)
    {
     getc(stdin);
     printf("\nI'm sorry, you have input an unrecognized value, please input a numeric digit for 'a':\t");
     scanf_s("%lf", a);
     if (*a > 2000000000 || *a < -2000000000)
     {
      wrong_a(a);
     }
     printf("Thank you.\n\n");
    }
    void wrong_b(double* b)
    {
     getc(stdin);
     printf("\nI'm sorry, you have input an unrecognized value, please input a numeric digit for 'b':\t");
     scanf_s("%lf", b);
     if (*b > 2000000000 || *b < -2000000000)
     {
      wrong_b(b);
     }
     printf("Thank you.\n\n");
    }
    void wrong_c(double* c)
    {
     getc(stdin);
     printf("\nI'm sorry, you have input an unrecognized value, please input a numeric digit for 'c':\t");
     scanf_s("%lf", c);
     if (*c > 2000000000 || *c < -2000000000)
     {
      wrong_c(c);
     }
     printf("Thank you.\n\n");
     return c;
    }
    PS. Sorry if the code seems scrunched, still not quite used to posting on here, and the copy/paste wasn't wanting to behave haha...

  2. #2
    Registered User rstanley's Avatar
    Join Date
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    New York, NY
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    Blank lines between functions, and indentation of 2, 4, or 8 spaces.

    be careful about copy, and pasting from an IDE, as some hidden formatting will screw up the Code here. Only pure ASCII text!

    Can't compile and test right now.

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