I am new to those stuff i have to do a quadratic equation for school

Question

I have to make a quadratic equation in Microsoft Visual Studio.

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
    float a, b, c, D, x1, x2;
    printf("Type in a :\n");
    scanf_s("%d", &a);
    if (a == 0)
    {
        printf("The equation is not quadratic");
    }
    else
    {
        printf("Type in b:\n");
        scanf_s("%d", &b);
        printf("Type in c:\n");
        scanf_s("%d", &c);
        D = b*b - 4 * a*c;
        if (D < 0)
        {
            printf("There are no real roots");
        }
        else if (D == 0)
        {
            x1 = x2 = -b / (2 * a);
        }
        else
        {
            x1 = (-b + powf(D, 0.5)) / (2 * a);
            x2 = (-b - powf(D, 0.5)) / (2 * a);
        }
    }
    system("pause");
    return 0;
}

This is what I have done till now. Can you tell me where is my mistake? The studio isn't finding any mistakes, but there is a problem - after starting the program I type in a, b, and c and after that it says : "Press any key to continue" and when I do the console window disappears. Pls help

you need to print the solution, then wait for any input from the user.... — mlwn, Oct 23 '14 at 22:46
Do you want it to actually print the roots? You never tell it to do that. — clcto, Oct 23 '14 at 22:46
how about.. `printf("press any key to continue");` ... then `scanf_s(whatever);` — mlwn, Oct 23 '14 at 22:47
You really should test whether `scanf` succeeds or fails. Also, I suggest `sqrt` instead of `pow(x, .5)`, and why not go for `double`-precision? Finally, I really advice you to stay clear of `scanf_s` and such. — Deduplicator, Oct 23 '14 at 22:47
@Deduplicator not taking advantage of anything C++ has to offer. — Ryan, Oct 23 '14 at 22:48
@self: I see `float`, `printf`, `system`, loads of stuff. Please say how that's not C++. Also, you really want to suggest someone should write C on a MS-compiler? — Deduplicator, Oct 23 '14 at 22:50
@Deduplicator I'm just saying at first glance i don't see any distinct C++ features being used when you compare it to C — Ryan, Oct 23 '14 at 22:52
@self: I see MSVC, that's enough to say it won't be C (99% surety). — Deduplicator, Oct 23 '14 at 22:53

score 1 · Accepted Answer · answered Oct 23 '14 at 22:56

You are not printing the answer . . . for each case (real roots or not) you need to add a printf to print the calculated values of x1 and x2.

The line "pause" is the line that causes the "Press any key to continue . . . " so your program is reaching that point without error.

I am new to those stuff i have to do a quadratic equation for school

1 Answers1