Well-done, but can't compile

Hello gentle folks
I got this code

Code:

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#include <math.h>
#include <stdlib.h>
#include <stdio.h>


int main(void)
{
        float a, b, c;
        float delta;
        float x1, x2;
       
        printf("Risoluzione equazioni di secondo grado\n");
        printf("Equazione nella forma ax^2+bx+c=0\n");
       
        printf("Immetti il coefficiente a: \n");
        scanf("%f", &a);
        printf("Immetti il coefficiente b: \n");
        scanf("%f", &b);
        printf("Immetti il coefficiente c: \n");
        scanf("%f", &c);
        if ( a == 0 )
        {
                if ( b != 0 )
                {
                        x1 = -c / b;
                        printf("Una soluzione:x=%f\n", x1);
                }
                else
                {
                        if ( b == 0 )
                        {
                                printf("Equazione indeterminata: ammette infinite soluzioni\n");
                        }
                    else
                    {
                                printf("Equazione impossibile\n");
                        }
                }
        }
        else
        {
                delta = b*b - (4*a*c);
                printf("Il discriminante vale: %f \n", delta);
                if ( delta < 0 )
                {
                        printf("Non ci sono soluzioni in campo reale\n");
                }
                else if ( delta == 0 )
                {
                        x1 = -b / (2*a) ;
                        printf("Una soluzione doppia: x=%f \n", x1);
                }
                else
                {
                        x1 = ( -b - sqrt(delta) ) / ( 2 * a );
                        x2 = ( -b + sqrt(delta) ) / ( 2 * a );
                    printf("Due soluzioni x:%f e %f \n", x1, x2);
                }
        }
       
        exit(0);
}

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No mistakes, but i can't compile due to this warnings:
Attachment 15527
Can someone help me to understand?

Hello Alcatraz, my guess is that you have to link against the C math library to get the implementations of the functions in the math.h header. This seems to be a quirk in C.

So simply try adding -lm (a small L) to your compiler flags and see if that fixes it.

Attachment 15528
I tried,same error
If I try with "compile object" it tells me compilation well done but no file .exe is generated

What are "%e" and "%f"?

Only add -lm at the end of Build, after "%f", and nowhere else and see if that works.

Also, your IDE might offer a better way for adding libraries, please read the documentation on that.

->Which documentation do you mean? The IDE's one?
->"%e" and "%f" are standard, I didn't add those

It works now If i build btw. Thanks
If I press "compile everything" compiler tells me : "make: *** No targets specified and no makefile found. Stop."
If I press "compile object" compiler tells me: make: 'Esercizio-n11x.o' is up to date.

Quote:

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If I press "compile everything" compiler tells me : "make: *** No targets specified and no makefile found. Stop."

---

You might want to read your IDE documentation in case your setup uses a default makefile and target.

The way that make works is "make -f <makefile> <target>" when specifying a file and target, or "make <target>" when you have a default makefile. make automatically tries to read files with variations of the name "makefile". Here is a page with some quick instructions: ftp://ftp.gnu.org/old-gnu/Manuals/ma...er/make_9.html

Quote:

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If I press "compile object" compiler tells me: make: 'Esercizio-n11x.o' is up to date.

---

This is usually good, it means that you've made no changes since your last compile, so the compiler has nothing to do.

As a side note, because 'a' 'b' and 'c' are floats, you should do the following...

Code:

---

if (a == 0.0)
{
  ...

---